Amino acid & proteins chemistry

Amino acid & proteins chemistryAlmoeiz yousif2014Definitions

Amino acids are building blocks of protein.Proteins are polymers of amino acids linked by peptide bond.

Wednesday, December 03, 20142Importance of amino acids:

- building blocks of proteins-energy sourcePrecursors for non protein specialized productsWednesday, December 03, 20143Importance of protein:

1- enzymes 2- hormones3- structural4- transport 5- immunoglobulins6- clotting factors 7- complements8- buffers

Wednesday, December 03, 20144 Proteins are formed of a set of 20 amino acids. They are called standard amino acids. There are more than 300 amino acid in nature, only these 20 amino acids are found in protein from all living sources (bacteria, animal and plant).

Wednesday, December 03, 20145

Wednesday, December 03, 20146D& L amino acids:

Wednesday, December 03, 20147CLASSIFICATIONS OF AMINO ACIDSSide chain (R group) classificationNutritional classificationMetabolic classificationSolubility classificationWednesday, December 03, 20148 1.Classifying According to Side ChainClassification by structure of R:1. aliphatic amino acids2. aromatic amino acids3. acidic amino acids and derivatives4. basic amino acids 5. sulphur- containing amino acids 6. hydroxyl-containing amino acids 7. imino acid

Wednesday, December 03, 20149 Aliphatic amino acids

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Aromatic amino acidsWednesday, December 03, 201411Acidic Amino Acids and Their AmidesAspartic AcidAsparagineGlutamic AcidGlutamine

Wednesday, December 03, 201412Basic amino acidsR group = amineAccepts H+Positively charged

Wednesday, December 03, 201413Sulphur-containing Amino Acids

Wednesday, December 03, 201414Non-Aromatic Amino Acids with Hydroxyl R-Groups

SerineThreonineAromatic Amino Acids with Hydroxyl R-Groups

Tyrosine Wednesday, December 03, 201415Imino acid

Wednesday, December 03, 2014162.Dietary Classification of Amino AcidsSome amino acids can be formed from metabolic intermediates in the mammalian cells, thus are not necessary taken in food (Dietary non-essential) . Other amino acids must be obtained from diet, thus they are termed (Dietary essential)Wednesday, December 03, 201417Essential Amino Acids10 amino acids not synthesized by the bodyMust be obtained from the dietPhe, val, thr, trp, ile, met, his, arg, leu, lys.(adults are capable of synthesizing arginine and histidine, but these amino acids are believed to be essential to growing children.)

Wednesday, December 03, 201418Essential Amino AcidsNonessential

Essential

Alanine

Phenylalanine

AsparagineValine

Aspartate

ThreonineCysteineTryptophan

Glutamate

Isoleucine

Glutamine

MethionineGlycine

Histidine*

ProlineArginine*

Serine

LeucineTyrosine

Lysine

Wednesday, December 03, 2014193.Metabolic Classification of Amino AcidsAmino acids can also be classified according to the end product of their carbon skeleton catabolism into: 1. (Glucogenic Glucose producing)2. (Ketogenic Ketones producing)3. both glucogenic and ketogenic

Wednesday, December 03, 2014204.Solubility in waterHydrophilic amino acids ( polar ): dissolve in waterHydrophobic amino acids ( nonpolar ): do not dissolve in water

Wednesday, December 03, 201421The peptide bondeach amino acid links to the next with a peptide bond.A peptide bond results from the linkage of the carboxyl group of one amino acid to the amine group of its neighbor.Water is eliminated to form a peptide bond.

The Peptide Bond

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Wednesday, December 03, 201423Protein StructurePrimary : linear sequence of amino acidsSecondary: localized foldingTertiary: overall 3-D structureQuaternary: association of 2 or more protein subunits into a proteinWednesday, December 03, 20142424Levels of structure in proteins

Wednesday, December 03, 201425Proteins

Wednesday, December 03, 201426Quiz 1. Which amino acid contains sulfur in its side chain?SerineGlutamic acidGlutamineCysteineGlycine

Wednesday, December 03, 2014272. What is the covalent bond that link amino acids in protein?Van der Waals interactionsSalt bridgesHydrogen bondsPeptide bondsHydrophobic interactions

Wednesday, December 03, 2014283.The following amino acids are non-essential EXCEPT:Alanine.Leucine.Glutamic acid.Aspartic acid.Asparagine.

Wednesday, December 03, 2014294. Denaturation of a protein involves loss of its:Primary structureSecondary structure and tertiary structurePrimary and tertiary structurePrimary and quaternary structureAmino acids contents.

Wednesday, December 03, 2014305. Three dimensional refer to which protein structural level Primary structureSecondary structure Tertiary structureQuaternary structureAmino acids contents.

Wednesday, December 03, 2014316. Which of the following describes the side chain of valine?Contains a sulfhydryl groupContains a branched chain hydrocarbonContains an aromatic ringDoesn't have a side chainContains methyl group for a side chain

Wednesday, December 03, 2014327. All of the following forces may play a role in the formation of quaternary structure EXCEPTHydrogen bondsElectrostatic interactionsHydrophobic interactionsDisulfide bondsPeptides bonds.

Wednesday, December 03, 2014338. in point explain effect of physical extreme on proteins structure.9. protein play a role of buffer in human body ,discus .What is meaning of essential amino acid ,give an example .Wednesday, December 03, 20143434