Premium Call Girls In Jaipur {8445551418} ❤️VVIP SEEMA Call Girl in Jaipur Ra...
Enzymes & isoenzymes by Dr. Anurag Yadav
1. ENZYMEs
MNR MEDICAL COLLEGE & HOSPITAL
Dr Anurag Yadav
MBBS, MD
Assistant Professor
Department of Biochemistry
Instagram page –biochem365
YouTube – Dr Biochem365
Email: dranurag.y.m@gmail.com
2. OBJECTIVE
• What are enzymes?
• Definitions
• Characteristics of enzymes
• Classification of enzymes
4. BIOCHEMICAL NATURE OF ENZYME
• All enzymes are proteins except ribozymes.
• They are distinguished from other proteins by
catalytic action.
• The catalytic power of enzyme is d/u primary,
secondary, tertiary & quaternary structure of
the protein molecule.
• Change can affect enzyme activity.
5. Chemical Nature of Enzymes
• They are high molecular weight compounds
made up principally of chains of amino acids
linked together by peptide bonds.
• Enzymes can be denatured and precipitated
with salts, solvents and other reagents.
6. Characteristics
• Catalysts for biological reactions
• Most are proteins
• Lower the activation energy
• Increase the rate of reaction
• Heat labile
• Can be precipitated by protein precipitating
agents
• May contain cofactors such as metal ions or
organic (vitamins)
8
7. Substrate
• The substance upon which an enzyme acts.
Product
• The enzyme will convert the substrate into
product.
1/8/2021 9
8. Enzymes
Made of protein Present in
all living cells
Converts substrates
into products
Biological
catalysts
Increase the rate of
chemical reactions
Remain unchanged
by chemical reaction
Characteristics of enzymes
9. Name of Enzymes
• End in –ase
• Identifies a reacting substance
sucrase – reacts sucrose
lipase - reacts lipid
• Describes function of enzyme
oxidase – catalyzes oxidation
hydrolase – catalyzes hydrolysis
• Common names of digestion enzymes still use
–in
Pepsin, Trypsin
11
10. Enzyme classification
IUBMB System of Classification
• Described by International Union of
Biochemistry and Molecular Biology (IUBMB)
in 1964
12. Enzyme Code number
• “EC” Enzyme Code number
• 1st digit - main class.
• 2nd digit – subclass. Type of group involved.
• 3rd digit – sub-sub class
• 4th digit – number given to the enzyme in sub-
sub class
E.g. EC(1.1.1.27)
15. Classification of Enzymes
Class Reactions catalyzed
1. Oxidoreductoases Oxidation-reduction
2. Transferases Transfer group of atoms
3. Hydrolases Hydrolysis-cleave & add water
4. Lyases Cleave without adding water
5. Isomerases Rearrange atoms
6. Ligases Combine molecules using ATP
17
16. EC-1 OXIDOREDUCTASE
• Enzymes involved in oxidation- reduction reactions.
• Catalyze the electron transfer . Oxygen- oxidases.
Hydrogen- dehydrogenases.
Alcohol Dehydrogenase
Alcohol + NAD+ Aldehyde + NADH + H+
17. Class 1:
ENZYME SUBSTRATE PRODUCT
Lactate dehydrogenase Lactate Pyruvate
Xanthine oxidase Xanthine Uric acid
L Amino acid oxidase D amino acids Keto acids
Cytochrome oxidase Reduced Cytochrome C Oxidized Cytochrome-C
Alcohol dehydrogenase Alcohol Aldehyde
18. EC-2 TRANSFERASES
• Catalyze the transfer of functional groups.
(amino, carboxyl, methyl, phosphoryl, etc)
(A-X) +B A+(B-X)
19. A. METHYL group---e.g. Transmethylase
B. ALDEHYDE or KETONIC group e.g. Transaldolase
or transketolase.
C. ACYL GROUP e.g.Aceyltransferase
D. AMINO-KETO GROUP- Aminotransferase
E. KINASES are specialized transferase that
regulate metabolism by transferring phosphate
from ATP to other molecules e.g.
Hexokinase
ATP +Glucose -----G-6-P+ ADP
20. EC-3 HYDROLASES
• That bring about hydrolysis of compounds.
Catalyze the cleavage of C-O, C-N, C-C, etc by
adding water
A-B + H20 A-OH + B-H
Glucose-6-phoshate+H20 Glucose + Pi
glucose-6-phosphatase
22. EC-4 LYASES
• Catalyze the cleavage of C-O, C-C & C-N bonds by
means other than hydrolysis, giving rise to
compound with double bonds.
• A-X LYASE A
│ ║ + X-Y
B-Y B
• Ex- Aldolase, Decarboxylase, Carbonic Anhydrase,
Cysteine Desulfurase, HMG Co-A Lyase
23. EC-5 ISOMERASES
• Catalyze intramolecular (structural or geometric)
changes in a molecule.
ABC CAB
glucose,6,phosphate Fructose,6,phosphate
Phoshohexose isomerase
26. EC-6 LIGASES (Synthetases)
• Catalyze the joining of two molecules coupled with
the hydrolysis of pyrophosphate bond of ATP.
A + B + ATP AB + ADP +Pi
Glutamate+ NH3 + ATP
Glutamine synthatase
Glutamine +ADP+Pi
29. ZYMOGEN OR PROENZYME
• Enzymes which are present in inactive form, which
must be cleaved to be activated
• Blood & digestive tract- Enzymes present in
precursor form.
E.g. Chymotrypsinogen.
Prothrombin.
Proelastase
• Their synthesis in proenzyme form prevent them
from catalyzing reactions in the cell where they are
synthesized.
30. Co-enzymes
• Enzyme may be simple protein or complex protein
containing
protein part (Apo-enzyme)
+ Holoenzyme
non-protein part (Co-enzyme)
• Metallo-enzymes: enzymes which requires metal
ions for their activity. Ex: magnesium for
hexokinase
• Co-factors: Co-enzyme+Metal ion
31. Features of Co-enzymes
• Essential for the biological activity of the enzyme
• Co-enzyme is a low molecular weight organic
Substance
• It is heat stable.
• Combine loosely with the enzyme molecules
• when the reaction is completed, the co-enzyme is
released from the apo-enzyme, and can bind to
another enzyme molecule
• Most of the co-enzymes are derivatives of vitamin
B complex group of substances
08-01-2021 33
32. Co-enzymes may be divided into two groups
• Those taking part in reactions catalyzed by
oxidoreductases by donating or accepting
hydrogen atoms or electrons
• Those co-enzymes taking part in reactions
transferring groups other than hydrogen
08-01-2021 34
33. CLASSIFICATION
For transfer of hydrogen:
NAD+, NADP+, FMN, FAD, Lipoic acid,
Coenzyme Q.
For transfer of group other than hydrogen
Co-A-SH,
Thiamin pyrophosphate,
Pyridoxal phosphate,
Tetrahydro folate,
Biotin,
Methyl cobalamine
Deoxy adenosyl cobalamine
34. Dietary precursor Coenzymes Group transfer
Thiamin (B1) Thiamine
pyrophosphate
Aldehyde
Nicotinic acid
(Niacin )
Nicotinamide
adenine
dinucleotide
Hydride(H+)
Riboflavin (B2) Flavin adenine
dinucleotide
Electron
Panthothinic acid Coenzyme-A Acyl group
Pyridoxine Pyridoxial phosphate Amino group
36. LOCALIZATION OF ENZYMES
• Enzymes are located either
-Intracellularly or
-Extracellularly.
• Enzymes are found in all tissues and fluids of the body.
• Intracellular enzymes catalyze the reactions of
metabolic pathways.
• Plasma membrane enzymes regulate catalysis within
cells in response to extracellular signals
• Enzymes of the circulatory system are responsible for
regulating the clotting of blood
Almost every significant life process is dependent on
enzyme activity.
37. Site where actual reaction
occurs
Substrate –bound by weak
interaction
Specificity of enzyme
depend on arrangement of
atoms in active site
40. Specificity of Enzyme Action
• The ability of an enzyme to discriminate b/w two
competing substrates.
• Significance: specificity makes it possible for a
number of enzymes to co-exit in the cell without
interfering in each other’s actions.
• TYPES: - Absolute specificity
-Group specificity
- Reaction specificity
-Bond specificity
-Stereo specificity
42. Group specificity
• One enzyme can catalyse the same reaction
on a group of structurally similar compounds
• Ex- Hexokinase can catalyse phosphorylation
of glucose, galactose and mannose
• Lipase cleaves Various groups of Lipids
44. • Most of the proteolytic enzymes are showing
group (bond) specificity
• Ex- proteolytic enzymes
Exopeptidases Endopeptidases
-hydrolyzing terminal -centrally located
peptide bond peptide bond
-carboxypeptidase -pepsin, trypsin,
-aminopeptidase - chymotrypsin
Bond specificity
45. Stereo specificity
• Many enzymes show specificity towards
stereoisomers.
• They act on only one type of isomer
E.g: L-lactate dehydrogenase will act only on
L- lactic acid and not D- lactic acid
46.
47. How do enzymes Work?
Enzymes work by Lowering of
Activation Energy
1/8/2021 49
48.
49.
50. Enzymes accelerate reaction rate by
providing transition states with low
activational energy for formation of
products
Hence reaction rate is enhanced by many
folds in the presence of enzymes
The total energy of the system remains
the same and equilibrium state is not
disturbed
51.
52. • Theories to explain enzyme substrate
interaction
• Michaelis-Menten Theory
• Fischers Template Theory
• Koshland’s Induce Fit Theory
53. MICHAELIS–MENTEN THEORY
• In 1913 put forward the Enzyme–Substrate
complex theory
• The enzyme (E) combines with the substrate (S),
to form an enzyme-substrate (ES) complex,
which immediately breaks down to the enzyme
and the product (P)
• E + S → E–S Complex → E + P
54. Ex - Phosphatase
• Glucose-6-P → Glucose + Pi
• The active center of this enzyme contains a serine
residue
a. E-Serine-OH+Glucose-6-P→E-Serine-O-P+Glucose
b. E-Serine-O-P → E-Serine-OH+Pi
55. FISCHER'S TEMPLATE THEORY
Lock and Key Model
• It states that the three dimensional structure
of the active site of the enzyme is
complementary to the substrate
• Enzyme and substrate fit each other
56. KOSHLAND'S INDUCED FIT THEORY
• The substrate induces conformational changes
in the enzyme, such that precise orientation of
catalytic groups is effected
• Allosteric regulation can also be explained by
the hypothesis of Koshland
57. ENZYME KINETICS
• Enzyme kinetics is the study of the chemical
reactions that are catlysed by enzymes.
• In enzyme kinetics, the reaction rate is
measured and the effects of various conditions
of the reaction are investigated
58. • Velocity or rate of enzyme reaction is assessed
by the rate of change of substrate to product
per unit time
• The velocity is proportional to the conc. of
reacting molecules.
A + B -------------------------→ C + D
V α [A] [B]
59. FACTORS AFFECTING
ENZYME ACTIVITY
1. Enzyme concentration
2. Substrate concentration
3. Product concentration
4. Temperature
5. Hydrogen ion concentration (pH)
6. Presence of activators
7. Presence of inhibitors
8. Presence of repressor or derepressor
9. Covalent modification
60. 1. Enzyme Concentration
i. Rate of a reaction or velocity (V) is directly
proportional to the enzyme concentration
61. 3. Effect of Concentration of Products
• when product concentration is increased, the
reaction is slowed, stopped or even reversed
E1 E2 E3
A -------→ B ----------→ C -------||------→ D
63. • The temperature coefficient (Q10) is the
factor by which the rate of catalysis is
increased by a rise in 10°C.
• The rate of reaction of most enzymes will
double by a rise in 10°C.
65. • Enzymes have the optimum pH between 6 and
8.
Exceptions are
• pepsin (with optimum pH 1-2);
• alkaline phosphatase (optimum pH 9-10) and
• acid phosphatase (4-5).
66. 2. Effect of Substrate Concentration
• As substrate concentration is increased, the
velocity is also correspondingly increased in the
initial phases; but the curve flattens afterwards
• The maximum velocity obtained is called Vmax
69. Michaelis Constant (Km)
• Michaelis theory, the formation of enzyme–
substrate complex is a reversible reaction, while
the breakdown of the complex to enzyme +
product is irreversible
70. • The Michaelis-Menten equation
• It is relationship between initial reaction velocity
vi and substrate concentration [S]
• Km is Michaelis-Menten constant
71. • When Vo = ½ Vmax
Km = [S]
Km value is substrate concentration at half-
maximal velocity
72. Salient Features of Km
1. Km value is substrate concentration (expressed
in moles/L) at half-maximal velocity
2. Km is independent of enzyme concentration
3. It is the Signature of the enzyme
4. It denotes the affinity of the enzyme towards the
substrate
Low Km - high Affinity for substrate
High Km –low affinity for substrate
73. • Useful to compare Km for different substrates
for one enzyme
Hexokinase : D-fructose – 1.5 mM
D-glucose – 0.15 mM
• Useful to compare Km for a common substrate
used by several enzymes
Hexokinase: D-glucose – 0.05 mM
Glucokinase: D-glucose – 10 mM
74. Uses of Km
• Experimentally, Km is a useful parameter for
characterizing the number and/or types of
substrates that a particular enzyme will utilize
• It is the Km of the rate-limiting enzyme in many
of the biochemical metabolic pathways that
determines the amount of product and overall
regulation of a given pathway
75. Limitations of Michaelis-Menten equation
• Low [S] have to be used to plot the initial
segment where Vo cannot be measure precisely
• Very high [S] required to to draw a the final
platue
• When the points observed for velocity are too
scattered the hyperbolic graph cannot be drawn
precisely
• It is difficult to extrapolate the hyperbolic graph
if required
76.
77. • The plot provides a useful graphical method for
analysis of the Michaelis-Menten equation:
• Taking the reciprocal gives
V is the reaction velocity (the reaction rate)
Km is the Michaelis–Menten constant
Vmax is the maximum reaction velocity
[S] is the substrate concentration
80
79. ENZYME INHIBITION
Enzyme inhibitors -are molecular agents that
interfere with catalysis; slowing or halting
enzymatic reactions.
There are two broad classes of enzyme
inhibitors:
reversible and
irreversible
86. NONCOMPETITIVE INHIBITION
• Binding of the inhibitor does not affect binding of
substrate.
• No competition between substrate & inhibitor.
• Formation of both EI and EIS complexes is therefore
possible.
90. IRREVERSIBLE INHIBITION
• The irreversible inhibitors -
- Bind covalently with or destroy a functional group on
an enzyme that is essential for the enzyme’s activity,
91.
92. Examples
• Cyanide inhibits cytochrome oxidase.
• Fluoride will inhibit the enzyme, enolase, and consequently the
glycolysis.
• Iodoacetate inhibits enzymes having-SH group in their active
centers.
• BAL (British Anti Lewisite; dimercaprol) is used as an antidote for
heavy metal poisoning. The heavy metals act as enzyme poisons
by reacting with the SH group. BAL has several SH groups with
which the heavy metal ions can react and thereby their
poisonous effects are reduced
93.
94. Effect of inhibitors…
Type of inhibitor Km Vmax
Irreversible No effect Decreased
Reversible
competitive
Increased No effect
Reversible
noncompetitive
No effect Decreased
Reversible
uncompetitive
Decreased Decreased
95. • Increasing the substrate concentration will
abolish the competitive inhibition, but will not
abolish noncompetitive inhibition
96. Suicide inhibition
• It is a special type of irreversible inhibition of
enzyme activity. It is also known as mechanism based
inactivation.
• The inhibitor makes use of the enzyme's own
reaction mechanism to inactivate it (mechanism
based inactivation).
• the structural analog is converted to a more
effective inhibitor with the help of the enzyme to be
inhibited.
• This new product irreversibly binds to the enzyme
and inhibits further reactions
99. Competitive inhibition
Therapeutic agent Enzyme inhibited Clinical use
Acetazolamide Carbonic anhydrase Diuretic
Methotrexate Folate reductase Anti cancer
Captopril Angiotensin converting
enzyme
Hypertension
Statins HMG CoA reductase Hypercholesterolemia
Allopurinol Xanthine oxidase Gout
Dicoumarol Vit K epoxide reductase Anti coagulant
Sulphonamide Pteroid synthetase Antibiotic
Acyclovir DNAP of virus antiviral
100. Competetive inhibitors
Azaserine Phosphoribosyl
amidotransferace
Anti cancer
Cytosine arabinoside DNA polymerase Anti cancer
Neostigmine Ach esterase Myasthenia gravis
Osteltamivir Neuraminidase Influenza
Penicillin Transpeptidase Anti bacterial
Isonicotinic acid hydrazide Anti tubercular
101. Irreversible Inhibitors
Therapeutic agent Enzyme inhibited Clinical use
Cyanide Cytochrome oxidase
Fluoride Enolase Glycolysis inhibition
BAL (dimercaprol) Thiol group enzymes Heavy metal poisoning
Iodoacetate SH group containing enzymes Heavy metal poisoning
Suicide inhbition
Allopurinol Xanthine oxidase Gout
MAO inhibitors
(deprenyl)
Mono amine oxidase Mood stabilizers,
antidepressant .
102.
103.
104. Enzyme regulation
• The facility to increase or reduce the rate of an enzyme
catalysed reaction is a crucial part of metabolic control
and therefore the adaptability of metabolism as this
allows optimal utilization of possibly scarce resources.
• In short, a cell must be able to control its metabolic
activities in order to meet a challenge from the
environment.
105. Enzyme regulation …
• Rate limiting step of a metabolic pathway is
that reaction which determines the rate and
direction of the entire pathway
106. Criteria for rate limiting enzyme
• Regulated enzyme its activity and /or synthesis should be
regulated in vivo
• Rate limiting step is catalysed practically unidirectionally
or irreversible by the enzyme in vivo
• Determines the direction of the entire pathway
• Usually the initial step of a pathway so that the
intermediates of earlier steps would not accumulate in
case of feed back inhibition or repression of the rate
limiting enzyme.
110. Covalent modification
• Irreversible covalent modification
• Activation of inactive proenzymes or zymogens by
the action of partial Proteolysis (hydrolysis).
• Ex: trypsinogen, chymotrypsinogen, pepsinogen,
proinsulin, clotting factors, procollagen
111. Covalent modification
• Reversible covalent modification
• This is by the process of phosphorylation of
proteins on seryl, threonyl, or tyrosyl residues,
catalyzed by protein kinases, is
thermodynamically spontaneous.
• Equally spontaneous is the hydrolytic removal
of these phosphoryl groups by enzymes called
protein phosphatases.
112.
113.
114. Feedback regulation
• Feedback regulation, a phenomenologic term
devoid of mechanistic implications
• Ex: Dietary cholesterol decreases hepatic
synthesis of cholesterol
– Regulation in response to dietary cholesterol involves
curtailment by cholesterol or a cholesterol metabolite of the
expression of the gene that encodes HMG-CoA reductase
(enzyme repression)
115.
116. Allosteric Enzymes
• An important group of
enzymes that do not obey
Michaelis- Menten kinetics
comprises the allosteric
enzymes.
• These enzymes consist of
multiple subunits and
multiple active sites.
117.
118. • The activity of an allosteric enzyme may be altered
by regulatory molecules that are reversibly bound to
specific sites other than the catalytic sites.
• The catalytic properties of allosteric enzymes can
thus be adjusted to meet the immediate needs of a
cell.
• Allosteric enzymes are key regulators of metabolic
pathways in the cell.
119. Allosteric modulation
• The binding of substrate to one active site can
affect the properties of other active sites in
the same enzyme molecule.
• A possible outcome of this interaction
between subunits is that the binding of
substrate becomes cooperative : positive
allosteric effect
120. Allosteric modulation
• Negative cooperativity,
– in which the binding of substrate to one active site
decreases the affinity of other sites for substrate
• Negative allosteric modulation (also known
as allosteric inhibition) For example, when 2,3-
BPG binds to an allosteric site on hemoglobin,
the affinity for oxygen of all subunits
decreases
121.
122.
123.
124. Allosteric modulators
Enzymes Activators Inhibitors
Acetyl CoA caboxylase Citrate Palmitoyl CoA
Aspartate
transcarbamoylase
ATP CTP
Carbamoyl phosphate
synthase (mitochondria)
N acetyl glutamate
(cytoplasm) PP ribose P, ATP UMP, UDP, UTP, CTP
Fructose 1,6 bisphosphate Fructose 2,6 bisphosphate
Glycogen synthase Glucose 6 phosphate
Phosphofructokinase 1 Fructose 2, 6 bisphosphate ATP
Pyruvate carboxylase Acetyl CoA
125. Compartmentalization
• Pathways in eukaryotic cells are often
compartmentalized within cytoplasmic organelles by
intracellular membranes.
• Thus we find particular pathways associated with
the mitochondria, the lysosomes, the peroxisomes,
the endoplasmic reticulum
126. Compartmentalization
• Enzymes that degrade proteins and
polysaccharides reside inside lysosomes
• Fatty acid biosynthesis occurs in the cytosol,
whereas fatty acid oxidation takes place within
mitochondria
127. Induction
• Induction is effected through the process of derepression.
• The inducer will relieve the repression on the operator site
and will remove the block on the biosynthesis of the enzyme
molecules.
• Tryptophan pyrrolase and transaminases are induced by
glucocorticoids.
• Glucokinase is induced by insulin.
• ALA synthase is induced by barbiturates.
128. Repression
• repressor acts at the gene level.
• Whereas inhibition at enzyme level.
• key enzyme of heme synthesis, ALA synthase is autoregulated
by heme by means of repression
141. CLINICAL SIGNIFICANCE
Moderate increase (2-3 Times)
Alcoholic hepatitis
Infective hepatitis
High increase (10-12 Times)
Obstructive jaundice - Gall Stone
- Ca head pancreas
Very High Levels (10-25 Times)
-bone cancer
- Paget's disease
- Rickets
- Healing bone #
144. g-Glutamyl transferase GGT
FUNCTIONS
- Transfer of AA’s from one peptide to
another peptide
- Synthesis of glutathione
- Transport of aa across the cell
membrane
• Location:
-Liver, Kidney, Placenta
• Normal range : 10-30 U/L
145. CLINICAL SIGNIFICANCE
• More sensitive than ALP, NTP & AST, ALT
• Moderate increase – infective hepatitis
• Increased in Alcoholics – proportional to
Alcohol intake
• Liver carcinoma increased earlier than other
enzymes
149. CREATINE KINASE
Creatine CK Creatine phosphate
ATP ADP
• N Males -15-100U/L
• Females – 10-80U/L
• CK-MM – 80%
• CK-MB – 5%
• CK-BB – 1%
150. Clinical Significance
• CK-MB increased in MI
• CK-MM increased Mascular Dystrophies,
Crush Injuries
• CK-BB increased in Cerebrovascular accidents
151. LACTATE DEHYDROGENASE
PYRUVATE LDH LACTATE
• N- 100-200IU/L
• LDH levels are 100 times more inside the RBC
than in the Plasma
–Hemolysis – false +ve reasults
CLINICAL SIGNIFICANCE
• Increased in hemolytic anemia, hepatocellular
damage, mascular dystrophy, carcinomas,
leukemias , MI
157. AMYLASE
Amylase splits starch to dextrins,
maltose
Types – Salivary & Pancreatic
Normal range :
Serum - 50-120 U/L
urine - < 375 U/L
M W = 55,000
Optimum PH = 6.9 – 7
Calcium activates the enzyme
158. CLINICAL SIGNIFICANCE
Acute pancreatitis:
• 1000 times increase
• Rise within 2-12 hr
Peak – 12-72 hr
Normal – 3-4 days
• Moderate increase – chronic pancreatitis, mumps,
obstruction of pancreatic duct
• Urinary amylase increased in acute pancreatitis
increased on 1st day & remains increased for 7-10
159. LIPASE
• Hydrolyse Triglycerides
• Requires Colipase, bile salts
• N- 10-60U/L
• Location :
- Pancreas
• Increased in acute pancreatitis
• Increases within 4-8hrs, peaks 24hrs,
persists for 7-14 days
160. THERAPEUTIC ENZYMES
SL NO ENZYMES APPLICATION
1 Asperginase ALL
2 Streptokinase Lyse clot on MI
3 Pepsin & trypsin Used in GI disorders
4 Fibrinolysin Used on wounds
5 α1-antitrypsin Emphysema
6 Collagenase Debridement of dermal ulcers/burns
161. ENZYMES OF DIAGNOSTIC IMPORTANCE
ENZYMES TISSUE ORIGIN CLINICAL SIGNIFICANCE
1. Acid phosphatase Prostate, RBC Ca prostate
2. ALT Liver ,Muscle , heart liver disease
3. ALP Brain, Liver Bone & Hepatobiliary D
4. Amylase Pancreas Pancreatic disease
5. AST Heart, Liver MI, Hepatitis
6. Aldolase Skeletal muscle Muscular dystrophy
7. Cholinesterase Liver OP poisoning
8. Creatine kinase SM, Heart MI, Muscular dystrophy
9. GGT Hepatobiliary sys Hepatobiliary D, Alcohol
10. LDH Heart, Liver ,SM, RBC MI, Hemolysis
11. 5’-NTS Hepatobiliary tract Hepatobiliary disease
12. Prostate specific Ag Prostate Ca prostate
13. Lipase Pancreas Pancreatitis
14. Trypsin Pancreas Cystic fibrosis
166. ISOENZYME EP MOBILITY TISSUE OF
ORIGIN
MEAN %AGE
IN BLOOD
CK – 3
=MM
LEAST SKELETAL
MUSCLE
94%
CK – 2
=MB
INTERMEDI
ATE
HEART 5%
CK – 1
=BB
MAXIMUM BRAIN 1%
CHARECTERISTICS OF CK ISOENZYMES
167. LACTATE DEHYDROGENASE (LDH)
LD levels in tissues 500 times greater than
serum
levels (cytosolic)
Liver - 145 U/gm
Heart - 124 U/gm
Kidney - 106 U/gm
Skeletal muscle - 147 U/gm
RBC - 36 U/gm of Hb
