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Page 1: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Amino Acids

And

Protein

Page 2: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Organic compounds

Contains N in addition to C , H, O

Contains at least two functional groups -COOH and -NH2 attached to

ALPHA –C atom

They are building blocks of proteins

Essential for life

DEFINITION OF AMINO ACID

Page 3: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

GENERAL STRUCTURE OF

Α - AMINO ACID

L- α Amino acid

COOH

H H2N

R

C

Side chain defines

20 amino acids

Reference axis

Page 4: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

STRUCTURE OF Α - AMINO ACID

WHAT IS D & L FORM

CHO

OH H

CH2OH

C

D- Glyceraldehyde D- Amino acid L- Amino acid

COOH

H H2N

R

C

COOH

H NH2

R

C

Page 5: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

α Amino acids --- Natural amino acids

β – Amino acids -- β alanine, β taurine

γ -- Amino acids --- GABA,

L Amino acids - normal present in Human

D Amino acids - present in Bacteria and virus

TYPES OF AMINO ACIDS

Page 6: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

1. Components of peptides and proteins

2. Derivatives are components of lipids

3. Neurotransmitters or precursors of NT or

hormones

4. Glucogenic

5. Purine and pyrimidine Nitrogen base synthesis

FUNCTIONS OF AMINO ACIDS

Page 7: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

6. Non-proteinogenic AA are intermediate of

metabolic reactions

7. Forms active site in Enzymes

8. Acts as buffers at physiological pH -- Histidine

9. Transport oxygen and Carbon dioxide --

Histidine

10. Detoxification agents -- Glycine, Cysteine,

Taurine

FUNCTIONS OF AMINO ACIDS

Page 8: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

1. Based on their presence in protein

2. Based on R Group (side chain)

3. Based on Nutritional value

4. Based on metabolic fate

5. Based on polarity of side chain

VARIOUS WAYS OF

CLASSIFICATION

Page 9: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

CLASSIFICATION

BASED ON

R GROUP (SIDE CHAIN)

COOH

C H H2N

R

COOH

C H H2N

H

COOH

C H H2N

CH3

Page 10: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

A = Aliphatic amino acids

S = Sulphur containing amino acids

H = Hydroxyl group containing amino acid

A = Aromatic amino acids

B = Basic amino acids

A = Acidic amino acids

I = Imino acids

BASED ON R GROUP / SIDE

CHAIN

A

S

H

A

B

A

I

Page 11: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

G A V L I

Aliphatic amino acids

Contains open hydrocarbon side chain

Page 12: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Sulfur containing amino acids

Contains sulfur atom in their side chain

C C M

Page 13: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Hydroxyl group containing amino acids :

Contains hydroxyl / alcohol group in side

chain

S T

Page 14: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Aromatic amino acids

Contains closed ring hydrocarbon /

Phenyl ring as side chain

P T T

Page 15: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Basic amino acids

Contains more than 1 NH2 groups

in side chain --- H A L

Page 16: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Acidic amino acids

Contains COOH group OR their amides in

their side chain--- A G A G

Page 17: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Imino acids Contains secondary amino group in the

molecule

+

N

H2

COO_

Proline

Page 18: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Aliphatic –G A V L I

Sulphur containing – M C C

Hydoxyl group – S T

Acidic – A G A G

Basic – H A L

Aromatic – P T T

Imino – P HP

Page 19: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

CLASS 2

CLASSIFICATION OF AMINO ACIDS CONTINUE…

Page 20: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

BASED ON THEIR

PRESENCE IN

PROTEIN MOLECULE

Page 21: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

BASED ON THEIR

PRESENCE IN PROTEIN &

DNA CODE AVAILABILITY

PROTEINOGENIC

amino acids

Also called as STANDARD

amino acids

NON PROTEINOGENIC amino acids

Also called as METABOLIC amino

acids

Page 22: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

PROTEINOGENIC amino acids

The amino acids that are included in the genetic

Code are described as “PROTEINOGENIC.”

These amino acids can be incorporated

into proteins through translation.

Ex: Glycine, Alanine, Valine, Leucine, Isoleucine, serine, Threonine,

Methionine, Cysteine, Aspartic acid, Glutamic acid, Histidine, Arginine,

Lysine

Page 23: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

NON- PROTEINOGENIC amino acids Amino acids arise during

A. metabolic reactions - Ornithine, citrul ine, taurine

B. As result of enzymatic modif ications of amino acid residues in

peptides or proteins Cystine, Hydroxyproline

C. The “biogenic amines” synthesized from α - amino acids by

decarboxylation.

They don't have genetic Code

Page 24: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

BASED ON

NUTRITIONAL

REQUIREMENT

Page 25: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

CLASSIFICATION BASED ON NUTRITIONAL VALUE

Essential amino acids

or

non- dispensable amino acids

Non-Essential amino acids

or

Dispensable amino acids

M A T T V I L P H LY

Page 26: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

They are required by the body

Can be synthesized in the body

Not required to be supplemented through

diet

NON ESSENTIAL AMINO ACIDS

• A Alanine

• A Asparagine

• A Aspartate

• C Cysteine

• G Glutamate

• G Glutamine

• G Glycine

• P Proline

• S Serine

• T Tyrosine

• A

• A

• A

• C

• G

• G

• G

• P

• S

• T

Page 27: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

ESSENTIAL AMINO ACIDS

M Methionine

A Arginine

T Threonoine

T Tryptophan

V Valine

I Isoleucine

L Leucine

P Phenylalanine

H Histidine

Ly Lysine

Required by the body

Cannot be synthesized in the body

Must be supplemented through diet

Deficiency leads to improper protein synthesis

and may leads to disease

• M

• A

• T

• T

• V

• I

• L

• P

• H

• Ly

Page 28: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

ESSENTIAL AMINO ACIDS

Absolute essential

Not at all synthesized in the body

100% supply through diet

Semi essential

Small quantity synthesized

in body

Not sufficient to meet the

metabolic need

Partly supplied through

diet

Ex Histidine Arginine

Page 29: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Sources of essential

amino acids

Cysteine spare Methionine and Tyrosine spare

phenylalanine

In PKU Tyrosine becomes essential amino acid.

Complete proteins

Milk casein,

egg albumin,

animal proteins

contains all EAA

Page 30: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Blend diet

Page 31: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Required for proper growth of individual.

It help to maintain proper nitrogen balance

To synthesize normal new protein to replace old.

High quality protein diet is required for

Renal disease, Geriatric group, recovery from illness,

pediatric group.

Deficiency leads to PEM and improper growth.

WHY EAA ARE REQUIRED?

Page 32: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

1. Ketogenic Amino acids

CLASSIFICATION BASED ON METABOLIC FATE

2. Glycogenic

Amino acids

3. Ketogenic and Glycogenic

amino acids

Page 33: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

On deamination carbon skeleton gives Ketogenic

intermediates like acetoacetate, Acetyl CoA

Excessive intake causes ketonuria and ketosis

Ex: Leucine , Lysine

KETOGENIC AMINO ACIDS

Page 34: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

On deamination carbon skeleton forms

glycogenic intermediates like Propionic acid,

Succinic acid, Pyruvic acid, Oxaloacetate, α –

Ketoglutarate

Ex: Glycine , Alanine, Threonine, Cysteine, Valine, Methionine,

Aspartate, Glutamiate

GLYCOGENIC AMINO ACIDS

Page 35: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

On deamination carbon skeleton gives

Ketogenic intermediates like

acetoacetate, ------ -Phe, Tyr, Trypto

Acetyl CoA , -------- Isoleucine

And also glycogenic intermediate like

fumarate ------------- Phe & Tyr.

pyruvate --------- Tryptoaphane

propionate --------- Isoleucine

GLYCOGENIC AND KETOGENIC AMINO

ACIDS

Phenylalanine

Tyrosine

Tryptophan

Isoleucine

Page 36: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1
Page 37: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

1. Based on their presence in protein

2. Based on R Group (side chain)

3. Based on Nutritional value

4. Based on metabolic fate

5. Based on polarity of side chain

VARIOUS WAYS OF

CLASSIFICATION

Page 38: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Class 3

Reactions of

amino acids

Page 39: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

COOH

H C H3N+

R

COOH

H H2N

R

C COO

_

H C H2N

R

Low pH Acidic

High pH Basic

Amino acid

Anionic form

Cationic form

Ionization of amino

acids

Page 40: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

What is Zwitter ion?

What is Amphoteric molecule?

What is Isoelectric pH?

Page 41: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1
Page 42: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Different types of amino acids undergo polymerization

by peptide bond formation

Peptide bonds are important part of protein structure.

If they are broken or hydrolyzed it degrade protein

PEPTIDE BONDS Amino acids

Dipeptide

Tripeptides

Peptides

Polypeptides (Proteins)

Page 43: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

PE

PT

IDE

BO

ND

FO

RM

AT

ION

H

H2N

R

C C OH

O II

COOH

H

R

C N

H

H

H

H2N

R

C C

O II

COOH

H

R

C N

H

HO H

Page 44: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Composed of small number of amino acids

Linkage is peptide bonds

Synthesized in body

Have specific function

Digestion of protein also leads

PEPTIDES

Page 45: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

BIOLOGICALLY IMP PEPTIDES

Page 46: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Hormone : Insulin, glucagon, Vasopressin, Oxytocin

Antioxidant : Glutathione

Antibiotics : Gramicidin S

Anti-tumor drug : Bleomycin

Sweetening agent : Aspartame

EXAMPLES AND BIOMEDICAL IMPORTANCE

Page 47: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Tripeptide : Glutamic acid, Cysteine and Glycine

Reduced form as GSH

Oxidised form as GS-SG

Characterised by Gama peptide bonds,

not digested by peptidase

Found in all cell except nerve cell

Biological antioxidant, Amino acid absorption

BIOLOGICALLY IMP PEPTIDES

Glutathione

Page 48: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Functions:

1. Coenzyme in oxidation reduction reaction

2. Maintains Red Cell Membrane integrity

3. Protects HB against Oxidation

4. Free radical and peroxide scavanging

5. Detoxication

BIOLOGICALLY IMP PEPTIDES

Glutathione

Hemolytic anemia due to G6PD deficiency

Page 49: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

from β cell of pancreas

Contains 30 + 21 amino acids

Hypoglycemic Hormone

INSULIN

Glucagon

from α cell of pancreas

Contains 29 amino acids

Hyper glycemic hormone

Page 50: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Angiotensinogen synthesized by liver

Angiotensinogen to angiotensin I by Renin (10 AAs)

Angiotensin I to II by ACE (Angiotensin converting enzyme)

Angiotensin II active form Have 8 AAs

Vaso-constructor increase arterial pressure

Increase synthesis of Aldosteron -Na+ retention

ACE inhibitors used as antihypertensive & CCF

ANGIOTENSIN

Page 51: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Hormone of posterior pituitary

Contains 9 amino acids

Stimulates contraction of uterus

OXYTOCIN

Hormone secreted by posterior pituitary

Contains 9 amino acids

Decreases GFR and retains body water

Increases Blood pressure

Vasopressin (ADH)

Page 52: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Hormone of Anterior pituitary

Contains 39 amino acids

Stimulates adrenal cortex for secretion of steroid hormones

CORTICOTROPIN

TRH

Hypothalamic hormone

Contains 3 amino acids

Stimulates release of thyrotropin from anterior pituitary

Page 53: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Local hormone from Stomach

Stimulates production of gastric juice

GASTRIN

Secretin

G I Peptide

Stimulates secretion of pancreatic juice

Page 54: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Contains 9 amino acids

Formed in blood

Power full vasodilator

Causes contraction of smooth muscles

Stimulates pain receptors

BRADYKININ

Enkephalins

Peptide formed in CNS

Binds to certain receptors in brain and induces

analgesia (Killing pain sensation)

Page 55: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Contains 10 amino acids

Power full vasodilator

KALLIDIN

Aspartame

Di-peptide,

Neutra sweet, artificial sweetener

L aspartyl phenylalanyl methyl ester

Not suitable for phenylketourics.

Page 56: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

IMPORTANT REACTIONS

OF

AMINO ACIDS

Page 57: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Removal of amino group from amino acid by enzyme to

forms keto acid

Deamination:1. Oxidative deamination

2. Non oxidative deamination

DEAMINATION

Glutamate α keto glutarate

NH2

Amino acid deaminase

Page 58: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Transfer of amino group of one amino acid to a keto

acid

Result in formation of new amino acid and a keto acid

Enzymes : Transaminase or

Amino transferase

Coenzymes : Pyridoxal phosphate

Advantage: Non essential amino acid synthesis

Interconversion of amino acids

TRANSAMINATION

Page 59: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Amino acid

α ketoacid Amino acid

α ketoacid Amino transferase

Pyridoxal phosphate

General reaction

Alanine

α ketoglutarate L- Glutamate

Pyruvate Alanine transaminase

Pyridoxal phosphate

Page 60: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Acidic amino acids reacts with NH3 to form amide.

They are part of protein structure

Serve as source of Nitrogen

REACTION WITH AMMONIA

L- Glutamate

L- Glutamine

α keto glutarate

NH3 NH3

Enzyme - Glutaminase

Page 61: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Sulphur containing amino acid during their catabolism

oxidises sulph-hydryl group to form keto acid.

DESULPHURATION

C

COOH

CH2

SH

NH2 H

SH2

COOH

CH3

NH C

COOH

CH2

NH2 C

COOH

CH3

C O

Cysteine

Desulphurase

Imino acid Keto acid

Page 62: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

DECARBOXYLATION Removal of coo group to form amines

Enzymes : Amino acid decarboxylase

Coenzyme : Pyridoxal phosphate

Glutamate GABA

Neurotransmitter

Histidine Histamine

Effect on BP, Allergic cond

Tyrosine Tyramine

Contracts uterus

Tryptophan Tryptamine

Serotonin, NT

Decarboxylase

PLP

CO2

Page 63: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

COLOUR REACTIONS OF AMINO ACIDS

Biuret reaction Peptide bonds

Ninhydrine reaction Free amino groups

Xanthoproteic reaction Aromatic amino acids

Millon’s reaction Tyrosine

Hopkins – cole reaction Tryptophan – indole ring

Sakaguchi’s reaction Arginine – guanidino group

Nitroprusside reaction Free SH group

Pauly’s reaction Histidine – imidazole group

Lead acetate reaction SH group

Page 64: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

BIOLOGICALLY IMPORTANT

COMPOUNDS FROM AMINO ACIDS

Glycine Heme, Purine base, Bile salt, Glutathione

Aspartic and Glutamic acid

Purine, pyrimidine bases

Tyrosine Thyroxine, Adrenaline, Melaniine, Tryptamine

Tryptophane Niacin, Serotonin

Arginine, Methionine, Glycine

Creatine

Page 65: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Last edited Nov 2018

1. Describe biomedical significance of five biologically active

peptides.

2. List two examples of dipeptide and their biomedical

importance.

3. List amino acids present in glutathione . Write its

significance.

4. What is ADH? Write its function.

5. Define Zwiter ion and write its significance.

6. Explain amphoteric nature of amino acid.

7. List Branched chain and Aromatic amino acids.

8. Describe classification of amino acids.

Page 66: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

CLASS 4

Classification based on Nutritional Value

& Shape of proteins

Page 67: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Organic compounds

Contains C, H,O, N, AND P ,S

Mixed polymer of amino acids

Linked together by peptide bonds

PROTEINS

N terminal C terminal

H2N COOH

Polypeptide / Protein

n

Page 68: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

1. Based on Functions

2. Based on Nutritional value

3. Based on Shape & Structure

4. Based on Chemical composition

CLASSIFICATION OF PROTEINS

Page 69: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Nutritional value is determined by the presecence of

essential amino acids

CLASSIFICATION BASED ON

NUTRITIONAL VALUE

1. Complete Proteins - 1st class proteins

2. Incomplete Proteins

3. Partially Incomplete Proteins

Page 70: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Complete Proteins - 1st

class proteins

All essential amino acids

present in proper proportion

Good for health and

balanced growth

Egg protein, Milk proteins,

Fish, meat, cheese

CLASSIFICATION BASED ON

NUTRITIONAL VALUE

Incomplete Proteins

Lack one or more essential

amino acids

Can not support expected

growth and health completely

Proteins from plants and

cereals, beans, nut , Gelatin

Food blend is the solution

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Proteins contains essential amino acids

but not enough to meet the metabolic

need of organism

EX: Proteins from Wheat , Rice , Corn

PARTIALLY INCOMPLETE

PROTEINS

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Classification based on

Physical Shape and Structure

Over all shape is determined on the

basis of AXIAL RATIO

i.e. Length / Width ratio

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Classification based on

Physical Shape and Structure

Fibrous Proteins

Length

width

Fibrous Proteins

Axial ratio more than 10

Length : width ratio is more than

10

Molecules are elongated

Show helix, H bond, covalent

bond

Play structural role

Myosin, Actin, Keratin, Fibrin, Collagen,

Elastin, Tropomyosin

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Classification based on

Physical Shape and Structure

Globular Proteins

Length

width

Globular Proteins

Axial ratio generally 3 or 4

Length : width ratio is less than 10

Molecule is Spherical / Oval

Easily soluble in water ,

Digestible

Play dynamic functions

Albumin, Globulin, Protamines,

Enzymes

Page 75: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Fibrous Proteins

Play structural role

Insoluble in water ,

non -digestible

Myosin, Actin, Keratin, Fibrin,

Collagen, Elastin

Globular Proteins

Soluble in water, digestible

Play dynamic functions

Albumin, Globulin, Protamines

Classification based on

Physical Shape and Structure

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Mechanical function

Provide strength contractile character

Provide net work for calcification of bone

FUNCTIONS OF FIBROUS

PROTEIN

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Dynamic proteins

Enzymes

Hormones

Carrier proteins

Nutritive and oncotic pressure

FUNCTIONS OF GLOBULAR

PROTEIN

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NEXT CLASS

FUNCTIONAL CLASSIFICATION

OF PROTEIN

Page 79: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Organic compounds

Contains C, H,O, N, AND P ,S

Mixed polymer of amino acids

Linked together by peptide bonds

PROTEINS

N terminal C terminal

H2N COO

H

Polypeptide / Protein n

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CLASSIFICATION OF

PROTEIN

BASED ON FUNCTION

Page 81: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Hi ! Genetic Structure Of cat

Was Contractile

Hence Transported For

Protection , but

Eaten up (Nutritional)

Page 82: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Some hormones are protein in nature

They regulate metabolic pathways by fine tuning

E.g. Insulin, Glucagon, Growth hormone

HORMONAL PROTEIN

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Immunoglobulins and Antibodies are proteins synthesized against antigen.

They provide immunity and help in defence.

E.g. Immunoglobulins –G,A,M,D,E, Acute phase proteins.

IMMUNO PROTEIN

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Basic proteins, always found in association with Nucleic acid – DNA.

It provide stability to the DNA structure,

E.g. Nucleoproteins (Histones), Repressor proteins, Inducer proteins, SSBP.

GENETIC PROTEIN

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This class of protein provides structural frame work for cell and organs.

E.g. Keratin, Collagen, Actin, Myosin, Elastin, Fibroin,

STRUCTURAL PROTEIN

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Also called ENZYMES

Class of protein act as catalyst in metabolic reactions and speed up the reaction rate.

E.g. Amylase, Pepsin, Trypsin, Lipase.

CATALYTIC PROTEIN

Page 87: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Class of protein responsible for movement.

E.g. Actin, Myosin, Tubulin, Flegella, cilia.

CONTRACTILE PROTEIN

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Protein which help in transport of molecules and metabolites inside the cell or across the cell.

E.g. Hemoglobin, Ceruloplasmin, Transferin, Lipoproteins, Albumin, RBP, TBPA,

TRANSPORT PROTEIN

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Some proteins provide protection.

E.g. Fibrinogen, Prothrombin,

Receptor proteins,

PROTECTIVE PROTEIN

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Some proteins provide good nutrition when consumed in proper amount.

E.g: Casein, Albumin, Lactalbumin, Gliadin, Oricin,

NUTRITIVE PROTEIN

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Page 92: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Chemical Classification of

Proteins

CLASS 6

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Organic compounds

Contains C, H,O, N, AND P ,S

Mixed polymer of amino acids

Linked together by peptide bonds

PROTEINS

N terminal C terminal

H2N COOH

Polypeptide / Protein

n

Page 94: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Classification based on

Chemical composition

Page 95: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

CLASSIFICATION BASED ON

CHEMICAL COMPOSITION

Simple proteins

Conjugated proteins

Derived proteins

Contains only amino acids

Contains amino acids and non protein part called prosthetic part

Hydrolysed, degraded or denatured product of simple or conjugated protein

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Composed of only amino acids, linked by peptide bonds

SIMPLE PROTEINS

Albumins

Globulins

Albuminoids /Scleroprotein

Globins

Histones

Prolamines

Protamines

Glutelins

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SIMPLE PROTEINS

Albumins : Soluble in water, Heat coagulated , Precipitated at full saturation EX: Serum Albumin, Ovalbumin, Lactalbumin

Globulins : Soluble in water & in dilute salt solutions Coagulated by heat, Precipitated at half saturation , EX: Serum Globulins, Ovoglobulin, Lactglobulin, Legumin of pea

A

G

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SIMPLE PROTEINS

Albuminoids / Scleroproteins: Insoluble in water, Salt solution, Acid, Alkali

Not coagulated by heat , not precipitated

EX: Collagen, Keratin, Elastin,

Globins : Soluble in water, dilute acid and alkali

Soluble in neutral salt solutions

Not Coagulated by heat, Basic proteins

EX: Globins of Hemoglobin and Myoglobin

A

G

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SIMPLE PROTEINS Histones: Basic proteins rich in histidine , Soluble in water, mainly found in association with nucleic acid and gives stability to the genetic material, not coagulated EX: Histones of nucleoproteins , Thymus

Protamine : Basic protein, Soluble in water, Dilute alkali and

dilute acid, Not Coagulated by heat, Relatively small

proteins, rich in Arginine and Lysine,

EX: Zinc insulinate, Nucleo-protein of sperm ,

Salmine

H

P

Page 100: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

SIMPLE PROTEINS Prolamines: Insoluble in water, soluble in dilute alcohol,

Not coagulated by heat EX: Proline rich protein

of plants deficient in lysine, Gliadin of wheat,

Zein of maize

Glutelins : Insoluble in water, Soluble in salt solutions

Coagulated by heat, Found in plants

EX: Glutelin of wheat, Oryzenin of rice

P

G

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Proteins linked to non-protein groups called prosthetic

groups

CONJUGATED PROTEINS

Glycoproteins

Phosphoproteins

Lipoproteins

Nucleoproteins

Chromoproteins

Metaloproteins

Flevoproteins

Page 102: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

CONJUGATED PROTEINS

Glycoproteins : Carbohydrate as prosthetic group

EX: Ovomucin, Ovomucoid, mucoprotein,

Blood group antigen, receptors on cell membrane

Phosphoproteins : Phosphate / phosphorus as prosthetic group

EX: Casein, Ovo-vitelline

G

P

Page 103: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

CONJUGATED PROTEINS

Lipoprotein: Lipid in association of apo-protein

Lipid is prosthetic group

EX: Chylomicrone, VLDL, HDL, Membrane

lipoproteins, milk protein

Nucleoprotein : Nucleic acid or nucleotide as the prosthetic

group

EX: Histones, nucleoprotein of thymus & sperm

L

N

Page 104: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

CONJUGATED PROTEINS

Chromo-proteins: Protein in association with coloured

prosthetic group, It impart colour to the proteins

EX: Hemoglobin , Visual purple,

Metalo-proteins : Protein in association with metal ions

Metal activates the protein enzymes

EX: Zinc insulinate, Hemoglobin, Myoglobin,

Cytochroome, Carbonic unhydrase, Tyrosinase

C

M

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CONJUGATED PROTEINS

Flavoproteins: Riboflavin (Vitamin B2) in association with

proteins

EX: Riboflavin yellow (yellow enzyme of whey),

Flavanoids of liver and kidney

F

Page 106: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

FUNCTIONS OF CONJUGATED

PROTEINS Hemoglobin Heme Transport of O2 CO2

Cytochrome Heme Electron transport

Rhodopsin Retinal Vision

Casein Phosphrous Complete protein, High BVP

Lipoprotein Lipid Lipid transport & cell membrane

Ferritin Iron Iron storage normal form

Transferrin Iron Transport Iron

Ceruloplasmin Copper Transport copper, Enzyme

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Products obtained by hydrolysis, degradation or

denaturation of simple or conjugated proteins

DERIVED PROTEINS

Proteans

Meta-proteins

Coagulated proteins

Proteose

Peptones

Peptides

Primary derived Secondary derived

Page 108: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Products obtained by hydrolysis, degradation or

denaturation of simple or conjugated proteins

DERIVED PROTEINS

Proteans

Meta-proteins

Coagulated proteins

Primary derived

Earliest product of protein hydrolysis, Ex. Fibrin of fibrinogen

Product formed by concentrated acid or alkali, Ex. Paracaseinate, Acid metaprotein

Product of denatured protein, Ex. Coagulated Albumin,

Page 109: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Products obtained by hydrolysis, degradation or denaturation of simple or conjugated proteins

DERIVED PROTEINS

Proteoses

Peptones

Peptides

Secondary derived

Progressive hydrolytic product

of protein

Amino acids

Page 110: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Simple Conjugated Derived

Proteins

Albumin

Globulin

Albuminoid

Globin

Prolamine

Histone

Protamine

Glutelin

Glycoproteins

Phosphoproteins

Lipoproteins

Nucleoproteins

Chromo-proteins

Metalo-proteins

Flevo-proteins

Proteans

Meta-proteins

Coagulated proteins

Proteoses

Peptones

Peptides

Page 111: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

1. Define proteins. Write classification of protein based on

chemical composition.

2. What is simple protein? Name subclass with examples.

3. What is conjugated proteins? Name subclass with examples.

4. What is derived proteins? Name subclass with examples.

5. Name any five conjugated proteins and write their functions.

6. Name products of protein hydrolysis.

QUESTIONS

Page 112: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

FAILURE CAN NOT DEFEAT THE MAN WHO IS EAGER TO TRY AGAIN

Page 113: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

When two amino acids join together they form a

dipeptide.

When many amino acids are joined together a

long-chain polypeptide is formed.

Organisms join amino acids in different linear

sequences to form a variety of polypeptides, the

proteins.

Why variety of proteins?

Page 114: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Question is ---

How are they organised?

Page 115: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Primary

Secondary

Tertiary

Quaternary

ORGANIZATION OF PROTEIN

STRUCTURE

Assembly

Folding

Packing

Interaction

S T

R U

C T

U R

E

P R

O C

E S

S

Page 116: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Primary structure of protein Peptide bond

Amino acid

• Linear, Ordered, 1 dimensional sequence of AA polymer

• By convention, written from -NH2 end to -COOH end

• a perfectly linear amino acid polymer is neither functional

• nor energetically favorable needs folding

A V

L

A

P COOH G H2N

Page 117: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

PRIMARY STRUCTURE DEFECT

In β chain of hemoglobin 6th aa is Glutaminc acid ,

If Replaced by Valine forms Sickel cell Anemia.

Page 118: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

PRIMARY STRUCTURE DEFECT

Insulin from different sources Causes antibody and

immunological reactions.

A8 A9 A10 B30

Human Thr Ser Ile Thr

Pig Thr Ser Ile Ala

Cow Ala Ser Val Ala

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Poly peptide chain organise itself by folding

to become functional 3D molecule

This folding is stabilized by several types of bond

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SECONDARY STRUCTURE OF PROTEIN

Polypeptides become twisted or coiled.

These shapes are known as the secondary Structure.

There are two common secondary structures

1. The alpha-helix and

2. The beta-pleated sheet.

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Secondary structure

-- Alpha-helix

Each turn – 0.54 nm

Spacing between aa – 0.15 nm

Contains 3.6 aa residue / turn

Right handed and left handed coil

Amino acid

Hydrogen bond

0.5

4 n

m

3.6 aa

Peptide bond

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SECONDARY STRUCTURE

BETA PLEATED SHEET

Two peptide chains run parallel

Hydrogen bonds Hold shape together

Example Silk fibre

H2N

COOH

H2N

COOH

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Page 125: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

In secondary Str. polypeptides are held in

position by hydrogen bonds.

In both alpha-helices and beta pleated sheets

the C=O of one amino acid bonds to the H-N

of an adjacent amino acid to form hydrogen

bond.

HYDROGEN BONDS

STABILITY OF 2O STRUCTURE

Page 126: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Both secondary structures give additional strength to

proteins.

The alpha-helix helps make fibres like in your nails, e.g.

Keratin.

The beta pleated-sheet helps to make the strength giving

protein of silk, fibroin.

Proteins are made from both alpha-helix and beta-

pleated sheet in combination.

SECONDARY STRUCTURES

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A Protein will have both the forms of folding in their molecule

Bend or Knick

Glycine or Proline

Page 128: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Strength of protein--

Spider web can trap small insects, worms

and even bird or small animal

Giant spider web Greece Madagascar

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This is when a polypeptide is folded into a precise shape.

The polypeptide is held in ‘bends’ and ‘tucks’ in a permanent shape by number of bonds

including:

Disulphide bridges [sulphur-sulphur bonds]

Hydrogen bonds

Ionic bonds.

Hydrophobic and hydrophilic forces.

TERTIARY STRUCTURE OF PROTEIN

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TERTIARY STRUCTURE • Non-linear, 3 dimensional, Global but

restricted to the amino acid polymer.

• Formed and stabilized by

• Hydrogen bonding,

• Covalent (e.g. disulfide) bonding

• Hydrophobic packing toward core &

• Hydrophilic exposure to solvent

A globular amino acid polymer which is folded and

compacted becomes functional (catalytic)

and energetically favorable, ready for interaction.

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TERTIARY STRUCTURE OF PROTEIN

Page 132: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

QUATERNA

RY

STRUCTUR

E

• non-linear, 3 dimensional

• global, and Formed by distinct oligomers

• Stabilized by hydrogen bonding,

• covalent bonding,

• hydrophobic packing and

• hydrophilic exposure

• Thermodynamically favorable,

• functional structures

• occur frequently

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BONDS RESPONSIBLE FOR THE

STABILITY OF PROTEIN STRUCTURE.

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Protein structure is stabilized by two types of bonds

1. Covalent bonds and

2. Non-covalent bonds.

BONDS RESPONSIBLE FOR THE

STABILITY OF PROTEIN STRUCTURE.

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Peptide bonds:

Amino group of one amino acid condenses with

carbonyl group of another amino acid form peptide

bond.

back bone of the protein structure.

Not Brocken on Denaturation.

COVALENT BONDS

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Disulfide bond:

Formed between 2 cysteine residues.

Links 2 portions of polypeptide chains through a cystine

residue. ( S ---- S )

Resistant to the conditions of protein denaturation.

COVALENT BONDS

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They are weak bonds. Three major types

1] Hydrogen bonds:

Formed by the sharing of hydrogen atom between

nitrogen and carbonyl oxygen of different peptide bonds. (

Intra or Inter peptide)

Multiple hydrogen bonds stabilize the overall structure of

protein.

NON-COVALENT BONDS:

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Hydrophobic interactions:

Non polar side chain of neutral amino acids orient

them selves so as to form an association.

This tendency of large number of non polar groups give

stability to the protein structure.

NON-COVALENT BONDS:

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Electrostatic bonds or Salt Bridges :

Formed between oppositely charged groups

in the side chain of amino acids or

between N- terminal and C- terminal residue

interact electro statically and stabilize the structure of

protein.

NON-COVALENT BONDS:

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Van der waal’s forces:

Non covalent association between electrically neutral

molecules.

Overlapping of aromatic rings.

NON-COVALENT BONDS:

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DENATURATION OF PROTEINS

AND

ITS SIGNIFICANCE.

What happen if

bonds other than peptide bonds of protein

are broken?

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Disorganisation of secondary, tertiary and quaternary structure of

native proteins, without any change in primary structure.

DEFINITION DENATURATION OF PROTEINS:

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Physical agents:

Heat, UV light, mechanical shaking, Cooling

Chemical Agents:

Acids, Alkali, heavy metal, Organic Solvents and Alkaloids.

DENATURING AGENTS:

Page 145: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

1. Unfolding of native protein structure

2. Rupture of ionic, hydrogen bonds hydrophobic and

hydrophilic interactions.

3. Becomes more susceptible to proteolytic enzyme

4. Protein becomes insoluble in solutions.

5. Precipitated or coagulated.

6. Loses of its biological function and property.

DENATURATION OF PROTEINS LEADS TO

Page 146: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

1. Curdling of milk.

2. Preparation of egg omlet.

3. Formation of paneer.

4. Formation of Para caseinate in stomach.

5. Inactive / dormant enzymes.

6. Heat inactivated vaccines.

7. Precipitation of protein by neutral salt, alcohol, acetone.

EXAMPLES OF DENATURED PROTEINS

Page 147: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

1. Digestibility is increased.

2. Plasma proteins can be fractionated and Purified.

3. Property used in heavy metal poisoning as anti dot technique.

4. Preservation of food items and biological samples

SIGNIFICANCE OF DENATURATION

Page 148: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Ribonuclease is Denatured by 8M urea solution , when

urea is removed by dialysis Ribonuclease can be obtained

in its active form.

Bence Johns protein under go reversible Denaturation.

REVERSE OF DENATURATION

Page 149: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

Native state

Catalytically active

Unfolded state

Inactive, Disulphide cross links

reduced to yield Cys residue

Native state

Catalytically active

Disulphide cross links reformed

Reversible

Denaturation of

Ribonuclease

Page 150: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

1. Salting out and salting in.

2. Precipitation by organic solvents.

3. Precipitation at isoelectric point (pI)

4. Dialysis

5. Gel filtration

6. Centrifugation

7. Ion exchange and High performance, Affinity

chromatography

8. Electrophoresis

PROTEIN FRACTIONATION

Page 151: Amino Acids And Protein...α Amino acids --- Natural amino acids β – Amino acids -- β alanine, β taurine γ -- Amino acids --- GABA, L Amino acids - normal present in Human1

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