enzymes 1. history of enzymes -1700s and early 1800s, the digestion of meat by stomach secretions...
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ENZYMES
1
History of Enzymes
-1700s and early 1800s, the digestion of meat by stomach secretions and the conversion of starch to sugars by plant extracts and saliva were known.--mechanism by which this occurred had not been identified.
2
-19th century, when studying the fermentation of sugar to alcohol by yeast, Louis Pasteur came to the conclusion that it was catalyzed by a vital force contained within the yeast cells called "ferments", which were thought to function only within living organisms.
--He wrote that "alcoholic fermentation is an act correlated with the life and organization of the yeast cells, not with the death or putrefaction of the cells.
History of Enzymes
Yeast 3
1878: German physiologist Wilhelm Kühne first used the term enzyme, which literally means “in
yeast” 1897: Eduard Buchner
began to study the ability of yeast extracts that lacked any living yeast cells to ferment sugar. He also found that the sugar was fermented even when there were no living yeast cells in the mixture.
He named the enzyme that brought about the fermentation of sucrose "zymase". In 1907 he received the Nobel Prize in Chemistry “for his biochemical research and his discovery of cell-free fermentation".
History of Enzymes
4
Enzymes Enzymes are biomolecules that
catalyze, increase the rates of chemical reactions without being altered during the reaction. Almost all enzymes are proteins; Enzymes are essential to life.
In enzymatic reactions, the molecules at the beginning of the process are called substrates, and the enzyme converts them into different molecules, the products.
5
Almost all processes in a biological cell need enzymes in order to occur at significant rates.
Since enzymes are extremely selective for their substrates and speed up only a few reactions from among many possibilities, the set of enzymes made in a cell determines which metabolic pathways occur in that cell.
Enzymes
6
Enzymes Enzyme activity can be
affected by other molecules. Inhibitors are molecules
that decrease enzyme activity.
Inducers are molecules that increase activity. Many drugs and poisons are enzyme inhibitors.
Activity is also affected by temperature, chemical environment (e.g. pH),
7
Enzyme Inhibitor & Inducer
Enzyme Inhibitor Enzyme InducerCimetidine Rifampicin
Ketoconazole Carbamazepine
Fluconazole Phenobarbital
Miconazole Phenytoin
Macrolides(except Azithromycin)
Griseofulvin
Fluoroquinolones(except Levofloxacin)
Smoking
Chronic alcoholism8
ENZYMES are biological catalystENZYME CHARACTERISTICS1. The basic function of an enzyme is
to increase the rate of a reaction 2. Most enzymes act specifically with
only one reactant (called a substrate) to produce products
3. The most remarkable characteristic is that enzymes are regulated from a state of low activity to high activity and vice versa
9
Enzymes Lower a Reaction’s Activation Energy
10
Enzyme Action
11
Three-dimensional structure of an ENZYME
12
Enzymes are proteins
They have a globular shape
A complex 3-D structure
Three-dimensional structure of an ENZYME
Human pancreatic amylase
13
Enzyme Structure Most enzymes are proteins Enzymes may require a non-peptide
component as a cofactor. The peptide component is called the apoenzyme, the cofactor is called as the coenzyme and the combined functional unit is the holoenzyme
Cofactors that are tightly bound to the polypeptide are called prosthetic groups. Such proteins are called as complex or conjugated proteins. Proteins without prosthetic groups are simple proteins
14
The Active Site One part of an
enzyme, the active site, is particularly important
The shape and the chemical environment inside the active site permits a chemical reaction to proceed more easily
15
APOENZYME May be inactive in its original synthesized
structure
PROENZYME OR ZYMOGEN The inactive form of the apoenzyme May contain several extra amino
acids in the protein which are removed, and allows the final specific tertiary structure to be formed before it is activated as an apoenzyme
16
The Substrate The substrate of an enzyme are the reactants
that are activated by the enzyme; Enzymes are specific to their substrates; The specificity is determined by the active site.
17
An additional non-protein molecule that is needed by some enzymes to help the reaction
Nitrogenase enzyme with Fe, Mo and ADP cofactors
COFACTOR
18
COFACTOR
A non-protein substance which may be organic and called coenzyme
Common coenzymes are vitamins and metal ions
19
COFACTOR Another type of cofactor is an inorganic
metal ion called a metal ion activator Are inorganic and may be bonded through
coordinate covalent bonds Metal ions as Zn+2, Mg+2, Mn+2, Fe+2, Cu+2, K+,
and Na+1 are used in enzymes as cofactors
20
21
Vitamins as Coenzymes
Vitamin Coenzyme Function
Niacin
nicotinamide adenine
dinucleotide (NAD+)
oxidation or hydrogen transfer
Riboflavin flavin adenine
dinucleotide (FAD)
oxidation or hydrogen transfer
Pantothenic acid
coenzyme A (CoA) Acetyl group
carrier
Vitamin B12 coenzyme B-12 Methyl group
transfer
Thiamine (B1) thiaminpyrophosph
ate (TPP) Aldehyde group
transfer
22
PROSTHETIC GROUPS
Are tightly incorporated into protein structure by covalent or noncovalent forces
Examples include derivatives of B vitamins such as pyridoxal phosphate, flavin mononucleotide (FMN), flavin adenine dinucleotide (FAD), thiamin pyrophosphate, biotin and METAL IONS of Co, Cu, Mg, Mn, and Zn.
METALLOENZYMES – enzymes that contain tightly bound metal ions
23
PROSTHETIC GROUPS
24
NOMENCLATURE
The commonly used names for most enzymes describe the type of reaction catalyzed, followed by the suffix –ase. Dehydrogenases – remove hydrogen
atoms Proteases – hydrolyze proteins Isomerases – catalyze rearrangement
in configuration25
Modifiers may precede the name to indicate; (a) the substrate (xanthine oxidase)(b) the source of the enzyme (pancreatic ribonuclease)(c) its regulation (hormone-sensitive lipase)(d) a feature of its mechanism of action (cysteine protease)
NOMENCLATURE
26
Alphanumeric designators may be added to identify multiple forms of an enzyme ( eg., RNA polymerase III; protein kinase C )
Some enzymes retain their original trivial names, which give no hint of the associated enzymatic reaction Examples are pepsin, trypsin, and
chymotrypsin which catalyzes the hydrolysis of proteins
NOMENCLATURE
27
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Classification of Enzymes
Based on catalyzed reactions, the nomenclature committee of the International Union of Biochemistry and Molecular Biology (IUBMB) recommended the following classification:
1. OXIDOREDUCTASES Catalyze a variety of oxidation-reduction
reactions Common names include dehydrogenase,
oxidase, reductase and catalase
29
2. TRANSFERASES Catalyze transfers of
groups (acetyl, methyl, phosphate, etc.).
The first three subclasses play major roles in the regulation of cellular processes.
The polymerase is essential for the synthesis of DNA and RNA.
Classification of Enzymes
30
Three major regulatory chemical reactions. (a) Acetylation - addition of an acetyl group to lysine's R group by acetyltransferase. (b) Methylation - addition of a methyl group to DNA's
base (e.g. cytosine) by methylase. (c) Phosphorylation - addition of a phosphate group to the R group of tyrosine, serine or threonine (only tyrosine is shown here) by protein kinase.31
3. HYDROLASES Catalyze hydrolysis reactions where a
molecule is split into two or more smaller molecules by the addition of water
PROTEASES split protein molecules HIV protease is essential for HIV replication Caspase plays a major role in apoptosis
NUCLEASES split nucleic acids (DNA and RNA) Based on the substrate type, they are divided into
RNase and DNase. RNase catalyzes the hydrolysis of RNA DNase acts on DNA
Classification of Enzymes
32
Nucleases cont… They may also be divided into exonuclease and
endonuclease. The exonuclease progressively splits off single
nucleotides from one end of DNA or RNA. The endonuclease splits DNA or RNA at internal sites.
PHOSPHATASE catalyzes dephosphorylation (removal of phosphate groups). Example: calcineurin (also known as protein
phosphatase 3) The immunosuppressive drugs Tacrolimus,
Sirolimus, Everolimus and Cyclosporin A are the calcineurin inhibitors
Classification of Enzymes
33
4. LYASES
Catalyze the cleavage of C-C, C-O, C-S and C-N bonds by means other than hydrolysis or oxidation.
Common names include decarboxylase and aldolase.
5. ISOMERASES
Catalyze atomic rearrangements within a molecule.
Examples include rotamase, protein disulfide isomerase (PDI), epimerase and racemase
Classification of Enzymes
34
The role of rotamase and protein disulfide isomerase (PDI). The reactions
catalyzed by the two enzymes can assist a peptide chain to fold into a correct three-dimensional structure
35
6. LIGASES Catalyze the reaction which joins two molecules Examples include peptide synthase, aminoacyl-
tRNA synthetase, DNA ligase and RNA ligase
The IUBMB committee also defines subclasses and sub-subclasses
Each enzyme is assigned an EC (Enzyme Commission) number For example, the EC number of catalase is EC1.11.1.6 The first digit indicates that the enzyme belongs to oxidoreductase (class 1)Subsequent digits represent subclasses (1.11. acting on a peroxide as acceptor) and sub-subclasses (1.11.1peroxidases)
36
Mechanism of Enzyme Action
The molecule acted upon
a unique geometric shape that is
complementary to the geometric
shape of a substrate molecule
37
Mechanism of Enzyme Action
38
Mechanism of Enzyme Action
Lock and Key Theory first postulated in
1894 by Emil Fischer The lock is the
enzyme and the key is the substrate
Only the correctly sized key (substrate) fits into the key hole (active site) of the lock (enzyme)
39
The Lock and Key Hypothesis
Enzyme may be used again
Enzyme-substrate complex
E
S
P
E
E
P
Reaction coordinate 40
The Induced Fit Theory
Postulated by Daniel Koshland
It states that, when substrates approach and bind to an enzyme they induce a conformational change
This change is analogous to placing a hand (substrate) into a glove (enzyme)
41
The Induced Fit Theory Some proteins can change their shape
(conformation) When a substrate combines with an
enzyme, it induces a change in the enzyme’s conformation
The active site is then moulded into a precise conformation
Making the chemical environment suitable for the reaction
The bonds of the substrate are stretched to make the reaction easier (lowers activation energy)
42
The Induced Fit Theory
This explains the enzymes that can react with a range of substrates of similar types
Hexokinase (a) without (b) with glucose substratehttp://www.biochem.arizona.edu/classes/bioc462/462a/NOTES/ENZYMES/enzyme_mechanism.html
43
Assumes that the substrate plays a role in determining the final shape of the enzyme and that the enzyme is partially flexible.
This explains why certain compounds can bind to the enzyme but do not react because the enzyme has been distorted too much
Other molecules may be too small to induce the proper alignment and therefore cannot react
Only the proper substrate is capable of inducing the proper alignment of the active site
The Induced Fit Theory
44
This is a molecular model of the unbound carboxypeptidase A
enzyme
This is a representation of carboxypeptidase A with a
substrate (turquoise) bound in the active site. The active site is
in the induced conformation. 45
MECHANISMS TO FACILITATE CATALYSIS
A. CATALYSIS BY PROXIMITY For molecules to react, they must come within
bond-forming distance of one another The higher the concentration, the more
frequently they will encounter one another and the greater will be their rate of interaction
aka entropy reduction ACID-BASE CATALYSIS
Can be specific or general “Specific” meaning only protons (H3O+ ,
specific acid) or OH- ions (specific base)
46
Proximity: Reaction between bound molecules doesn't require an improbable collision of 2 molecules -- they're already in "contact" (increases the local concentration of reactants).
Orientation: Reactants are not only near each other on enzyme, they're oriented in optimal position to react, so the improbability of colliding in correct orientation is taken care of.
MECHANISMS TO FACILITATE CATALYSIS
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Rate enhancement by entropy reduction.
a) bimolecular reaction (high activation energy, low rate)
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b) unimolecular reaction, rate enhanced by factor of 105 due to increased probability of collision/reaction of the 2 groups.
Rate enhancement by entropy reduction.
49
c) constraint of structure to orient groups better (elimination of freedom of rotation around bonds between reactive groups), rate enhanced by another factor of 103, for 108 total rate enhancement over bimolecular reaction.
Rate enhancement by entropy reduction.
50
When substrate binds to enzyme, water is usually excluded from active site (desolvation). causes local dielectric constant to be lower,
which enhances electrostatic interactions in the active site, and also
results in protection of reactive groups from water, so water doesn't react to form unwanted biproducts.
Of course, if water is a substrate, it has to be "allowed in", but maybe only in a certain sub-part of active site.
Involvement of charged enzyme functional groups in stabilizing otherwise unstable intermediates in the chemical mechanism can also correctly be called "electrostatic catalysis".
MECHANISMS TO FACILITATE CATALYSIS
51
MECHANISMS TO FACILITATE CATALYSIS
CATALYSIS BY STRAIN Strain is created by binding to substrates in a
conformation slightly unfavorable for the bond to undergo cleavage
The strain stretches or distorts the targeted bond, weakening it and making it more vulnerable to cleavage
probably the most important rate enhancing mechanism available to enzymes
Enzyme binds transition state of the reaction more tightly than either the substrate or product --therefore DG‡ is reduced, and rate is enhanced.
52
Strain "Strain" is a classic concept in which it was
supposed that binding of the substrate to the enzyme somehow caused the substrate to become distorted toward the transition state. It's unlikely that there is enough energy available in substrate binding to actually distort the substrate toward the transition state.
It's possible that the substrate and enzyme interact unfavorably and this unfavorable interaction is relieved in the transition state.
It's more likely that the enzyme is strained, as for example in induced fit.
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Transition state stabilization is a more modern concept: it is not the substrate that is distorted but rather that the transition state makes better contacts with the enzyme than the substrate does, so the full binding energy is not achieved until the transition state is reached.
Induced fit assumes that the active site of an enzyme is not complementary to that of the transition state in the absence of the substrate. Such enzymes will have a lower value of kcat/Km, because some of the binding energy must be used to support the conformational change in the enzyme. Induced fit increases Km without increasing kcat.
MECHANISMS TO FACILITATE CATALYSIS
54
MECHANISMS TO FACILITATE CATALYSIS
COVALENT CATALYSIS Involves the formation of a covalent
bond between the enzyme and one or more substrates
Introduces a new reaction pathway with lower activation energy thus faster than the reaction pathway in homogenous solution
Common among enzymes that catalyze group transfer reactions
55
ENZYME KINETICSThe field of biochemistry
concerned with the quantitative measurement of the rates of enzyme-catalyzed reactions and the systematic study of factors that affect
these rates5656
ENZYME KINETICSREACTION MODEL
5757
where S is the substrate
E is the enzyme
ES is the enzyme-substrate complex
k1, k-1, and k2 are rate constants
MICHAELIS MENTEN EQUATION
Describes how reaction velocity varies with substrate concentration
vo = Vmax SKm + S
where Vo = initial reaction velocity
Vmax = maximal velocity
Km = Michaelis constant (k-1 + k2)/k1
S= substrate concentration
5858
ASSUMPTIONS1. Relative concentrations
of E and S S >E, so [ES] at any time is small
2. Steady-state assumption– [ES] does not change in time– E + S = ES = E + P, the rate of formation of ES is
equal to that of the breakdown of ES
3. Initial velocity– Used in the analysis of enzyme reactions– Rate of reaction is measured as soon as E and S
are mixed P is very small, the rate of back reaction from P
to S can be ignored5959
CONCLUSIONS1. Characteristics of Kma. Small Km
reflects high affinity of the E for S because a low concentration of S is needed to half-saturate the enzyme – that is, reach a velocity that is ½ Vmax
b. Large Km
Reflects low affinity of E for S because a high concentration of S is needed to half-saturate the enzyme6060
Effect of substrate concentration on reaction
velocities
Small Km for enzyme 1 reflects a high affinity of enzyme for the substrateLarge Km for enzyme 2 reflects low affinity of enzyme for the substrate
6161
CONCLUSIONS2. Relationship of velocity to enzyme
concentrationThe rate of reaction is directly proportional to the enzyme concentration at all substrate concentrations
3. Order of reactionFirst order - S < Km, the velocity of reaction is roughly proportional to the enzyme concentrationZero order - S > Km, the velocity is constant and equal to Vmax; the rate of reaction is then independent of substrate concentration
6262
At low concentration of substrate( [S]<<Km), The velocity of the reaction is first order – that is, proportional to substrate concentration
At
At high concentration of substrate( [S]>>Km), The velocity of the reaction is zero order – that is, constant and independent OF substrate concentration
6363
Lineweaver-Burk Plot
Also called a double-reciprocal plotIf 1/v0 is plotted VS 1/[S], a straight line is obtainedThe intercept on the x-axis is equal to -1/Km
The intercept on the y-axis is equal to 1/Vmax
6464
Lineweaver-Burk Plot
Can be used to calculate Km and Vmax as well as to determine the mechanism of enzyme inhibitorsEquation describing the Lineweaver-Burk Plot is:
6565
INHIBITION OF ENZYME ACTIVITY
INHIBITOR – substance that can diminish the velocity of an enzyme catalyzed reaction
TYPES OF INHIBITION:1. COMPETITIVE INHIBITION2. NONCOMPETITIVE INHIBITION
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COMPETITIVE INHIBITION Inhibitor binds
reversibly to the same site that the substrate would normally occupy, and therefore competes with the substrate for that site
Inhibitors tend to resemble the structures of a substrate, and thus are termed as substrate analogs
67
COMPETITIVE INHIBITION Malonate Malonate
(¯O(¯OCOCOCHCH22COO¯) COO¯) competes with Succinate competes with Succinate (¯OOC(¯OOCCHCH22CHCH22COO¯) COO¯) for the active site of for the active site of succinate succinate dehydrogenase (SDH)dehydrogenase (SDH)
SDH catalyze the SDH catalyze the removal of one H atom removal of one H atom from each of the 2 from each of the 2 methylene C’s of methylene C’s of succinatesuccinate
Succinate
Malonate
SDH
SDH
68
Succinate
(¯OOC-CH2-CH2-COO¯)
Fumarate
(¯OOC-HC=CH-COO¯)
-2H
Malonate – Enzyme Complex
NO REACTION69
Consequences of competitive inhibition
Vmax is unchanged: At high levels of substrate all of the inhibitor is displaced by substrate.
Km is increased: Higher substrate concentrations are required to reach the maximal velocity.
70
NONCOMPETITIVE INHIBITION
Inhibitor and substrate bind at different sites on the enzyme
The inhibitor binds to both E and ES
The noncompetitive inhibitor binds to an allosteric site (different location than the active site) of an enzyme
The binding of an inhibitor to the allosteric site alters the shape of the enzyme, resulting in a distorted active site that does not function properly.
71
Effect of Enzyme inhibition on Lineweaver-
Burk plot
72
NONCOMPETITIVE INHIBITION
Vmax is decreased: At high levels of substrate the inhibitor is still bound.
Km is not changed: Noncompetitive inhibitors do not interfere the binding of substrate to enzyme
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FACTORS AFFECTING ENZYME REACTIONS
I. SUBSTRATE CONCENTRATION
• The rate of enzyme catalyzed reaction increases with substrate concentration until a maximal velocity (Vmax) is reached
75
Effect of Temperature
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The rate of enzyme-catalysed reactions increases as the temperature rises to the optimum temperature
Above a certain temperature, activity begins to decline because the enzyme begins to denature
Enzymes are usually damaged
above about 45°C
Effect of pHEffect of pH
77
Each enzyme has an optimal pH
In order to interact, the E and S have specific chemical groups in ionized or unionized state
Amino group in protonated form (-NH3
+) increase catalytic activity
At alkaline pH, amino group is deprotonated decrease in rate of reaction
Extremes of pH can lead to denaturation
REGULATION OF ENZYME ACTIVITY
A. ALLOSTERIC REGULATIONB. REGULATION OF ENZYMES BY COVALENT MODIFICATION
78
A. ALLOSTERIC REGULATION
EFFECTORS – molecules that regulate allosteric enzymes that bind noncovalently at a site other than the active site Negative effectors – inhibit enzyme
activity Positive effectors – increases enzyme
activity
79
HOMOTROPIC EFFECTORS
Substrate itself serves as an effector Most often a positive effector The presence of a substrate
molecules at one site on the enzyme enhances the catalytic properties of the other substrate-binding sites(their sites exhibit cooperativity)
80
HETEROTROPIC EFFECTORS The effector may be different from the
substrate
81
Feedback Inhibition
82
B. REGULATION OF ENZYMES BY COVALENT MODIFICATION
Most frequently by the addition or removal of phosphate group from specific Ser, Thr, and Tyr residues of the enzyme
83
ADPATP
Enzyme-OH Enzyme-OPO3=
HPO4= H2O
Protein phosphatase
Protein kinase
Response of Enzyme to phosphorylation Phosphorylated form may be more or
less active than the unphosphorylated enzyme
Glycogen phosphorylase (degrades glycogen) activity is increased low activity (E), high activity (EP)
Glycogen synthase (synthesize glycogen) activity is decreased low activity (EP), high activity (E)
84
INDUCTION and REPRESSION
of enzyme synthesis Alter the total population of active sites rather than influencing the efficiency of existing enzyme molecules
Enzymes that are needed at only one stage of development or under selected physiologic conditions are subject to regulation of synthesis
Enzymes that are in constant use are NOT regulated by altering the rate of enzyme synthesis
85
Mechanisms for Regulating Enzyme Activity
86
Regulator event
Typical effector
Results Time required for
changeSubstrate
AvailabilitySubstrate Change in
velocityImmediately
Product inhibition
Product Change in Vmax and/or Km
Immediately
Allosteric control
End product Change in Vmax and/or Km
Immediately
Covalent modification
Another enzyme Change in Vmax and/or Km
Immediately - minutes
Synthesis or degradation of
enzyme
Hormone or metabolite
Change in the amount of
enzyme
Hours to days
Enzyme Activity is Often Regulated
Feedback inhibition - a common form of enzyme regulation in which the product inhibits the enzyme .
87
88
Enzymes - Activity Temperature and pH effect enzyme action
89
Enzymes - Activity Temperature and pH effect enzyme action
90
Enzymes - Activity Enzyme and substrate concentrations
91
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ENZYMES IN CLINICAL USE
Enzyme inhibitors as DRUGSEnzymes in CLINICAL DIAGNOSIS
93
Enzyme inhibitors as DRUGS
1. STATINS – HMG Coenzyme A reductase inhibitors; lower serum lipid concentration
2. EMTRICTABINE and TENOFOVIR DISOPROXIL FUMARATE – inhibitors of viral reverse transcriptase; block replication of HIV
3. ACE Inhibitors (Captopril, Lisinopril, Enalapril) – antihypertensive agents
4. Lactam Antibiotics (Penicillin and Amoxicillin) – inhibitors of alanyl alanine carboxypeptidase-transpeptidase, thus blocking cell wall synthesis
94
Enzymes in CLINICAL DIAGNOSIS
2 GROUPS OF PLASMA ENZYMES(1) Actively secreted into the plasma by
certain organs(2) Released from the cells during normal
cell turnover Intracellular, have no physiologic function
in the plasma Constant level in healthy individuals and
represent a steady state
95
Elevated enzyme activity in the plasma may indicate tissue damage
accompanied by increased release of intracellular enzymes, thus useful as a
diagnostic tool
Elevated levels of ALT (alanine
aminotransferase; also called
glutamate: pyruvate transaminase; GPT)
signals damage
96
ISOENZYMES
Also called isozymes Enzymes that catalyze the same reaction but
differ in their physical properties because of genetically determined differences in amino acid sequence
Different organs frequently contain characteristic proportions of different isoenzymes
Isoenzymes found in the plasma serve as a means of identifying the site of tissue damage
97
CK, Creatinine kinase
also called Creatinine phosphokinase (CPK) 3 isoenzymes; CK1, CK2, and CK3 Each isoenzyme is a dimer composed of 2
polypeptides (B and M subunits: CK1=BB, CK2=MB, CK3=MM)
CK2(MB) isoenzyme is present in more than 5% in myocardial muscles
Appears approximately 4 to 8 hours following onset of chest pain, and reaches a peak in activity at approximately 24 hours
98
LACTATE DEHYDROGENASE (LDH)
Elevated following an infarction peaking 3 to 6 days after the onset of symptoms
Of diagnostic value in patients admitted more than 48 hours after the infarction
99
Principal Serum Enzymes Used in Clinical Diagnosis
Serum Enzyme Major Diagnostic Use
AminotransferasesAspartate aminotransferase (AST, or SGOT)Alanine aminotransferase (ALT, or SGPT)
Myocardial infarction
Viral hepatitis
Amylase Acute pancreatitis
Ceruplasmin Hepatolenticular degeneration (Wilson’s disease)
Creatinine kinase Muscle disorders and myocardial infarction 100
Principal Serum Enzymes Used in Clinical Diagnosis
Serum Enzyme Major Diagnostic Use
-Glutamyl transpeptidase Various liver diseases
Lactate dehydrogenase (isoenzymes)
Myocardial infarction
Lipase Acute pancreatitis
Phosphatase, acid
Phosphatase, alkaline
Metastatic carcinoma of the prostate
Various bone disorders, obstructive liver diseases
101
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