This document discusses various enzymes used as diagnostic and therapeutic markers. It defines enzymes and their role in biological systems. It describes enzymes like ALT, AST, GGT, LDH, CK, ALP that are used to diagnose conditions like liver disease, myocardial infarction, muscle diseases. It explains how increased or decreased levels of these enzymes can indicate different pathological conditions. It also discusses enzymes like amylase and lipase that are markers for pancreatic disorders. Therapeutic enzymes mentioned include streptokinase, trypsin, asparaginase.

2.  Define enzyme
Enzymes are catalysts of biological
systems which are colloidal, thermolabile
& protein in nature.
Holoenzyme = Apoenzyme + Coenzyme

3.  Wroblewski in 1956 explain the role of SGOT &
LDH in diagnosing various conditions.

4.  Diagnostic markers
 Reagents for various biochemical estimations &
detections
 Therapeutic

5.  ALT/SGPT
 AST/SGOT
 GGT
 LDH
 CK
 ALP
 ACP
 5’ Nucleotidase
 Histaminase
 Pseudocholinesterase
 Aldolase
 Amylase
 Lipase
 Neuron specific enolase
 Leucine aminopeptidase
 β Glucuronidase

6. Enzyme Used for testing
Urease Urea
Uricase Uric acid
Glucose oxidase Glucose
Cholesterol oxidase Cholesterol
Lipase Triglycerides
Alkaline phosphatase ELISA
Horse radish Peroxidase ELISA
Restriction endonuclease Recombinant DNA
technology
Reverse transcriptase Polymerase chain reaction

7. Enzyme Therapeutic Application
Streptokinase/Urokinase Acute MI, Pulmonary embolism,
DVT(Deep vein thrombosis)
Trypsin, lipase and amylase Pancreatic insufficiency
Asparaginase/Glutaminase Acute lymphoblastic leukemias
Hyaluronidase Enhanced local anesthesia and for
easy diffusion of fluids
Papain Anti inflammatory
Chymotrypsin Pain killer and Anti inflammatory
Alpha- 1 Antitrypsin Deficiency and Emphysema
Serratopeptidase Pain killer and Anti inflammatory

8.  Sources of plasma enzymes are
 Plasma derived
 These act on substrates in plasma, and their
activity is higher in plasma than in cells.
e.g. coagulation enzymes
 Cell derived
 These have a high activity in cells and
overflow into the plasma.
 Subclassified as Secretory – Digestive
enzymes & Metabolic

9.  Cell derived enzymes enter plasma as a result
of
 Continuous normal ageing of cell
 Diffusion through undamaged cell
membranes
 They leave the serum
 Inactivation
 Catabolism in general protein pool
 Rarely excreted in bile and urine

10.  Increased release
 Necrosis of cell
 Increased permeability of cell without gross cellular
damage
 Increased production of enzyme within the cell
resulting in increase in serum by overflow
 Increase in tissue source of enzyme as in malignancy
 Impaired disposition
 Increased levels in obstructive jaundice
 Increased levels in renal failure

11.  Decreased formation which may be
 Genetic
 Acquired
 Enzyme inhibition
 Lack of cofactors

12.  A known amount of a substrate for the enzyme to
be assayed is incubated with serum.
 The product formed by the result of reaction is
allowed to react with a colour developing
substance which gives the characteristic colour.
 Measuring optical density using a colorimeter
helps in identifying the activity of the serum
enzymes.

13.  International Unit (IU/ml)
 One IU is defined as the activity of the enzyme
which transforms one μ mole of substrate per
minute under optimal conditions and at defined
temperature
 Katal Catalytic unit (Kat or K)
 One katal unit is defined as the number of mole
of substrate transformed per second per litre of
sample.

14.  Myocardial Infarction
 Creatine Phosphokinase
 Aspartate transaminase
 Lactate dehydrogenase
 γ Glutamyl transpeptidase
 Histaminase
 Pseudocholinesterase

15.  Liver diseases
 Transaminases (AST/ALT)
 Glutamate dehydrogenase
 Alkaline phosphatase
 Gamma glutamyl transferase
 5’ Nucleotidase

16.  Gastro intestinal tract diseases
 Amylase
 Lipase
 Muscle diseases
 Transaminases
 Aldolase
 Creatine phosphokinase
 Bone diseases
 Alkaline phosphatase

17.  Malignancies
Enzyme Disease
Serum acid phosphatase Cancer prostate
Serum Alkaline phosphatase Metastasis in liver, jaundice due
to carcinoma head of pancreas,
osteoblastic metastasis in bones
Serum LDH Advanced malignancies and
Leukemias
β Glucuronidase Cancer of urinary bladder
Leucine Amino Peptidase (LAP) Liver cell carcinoma
Neuron specific Enolase Malignancies of nervous tissue
and brain

18.  AST :
 Cytosolic and mitochondrial isoenzymes.
 Found in liver, cardiac muscle, kidneys, brain,
pancreas, lungs, leucocytes and red cells.
 Less sensitive and specific for the liver.
 ALT :
 A Cytosolic enzyme.
 Highest concentration in liver.
 More specific for liver.

19.  Most frequently used indicators of hepatocellular
necrosis.
 Normal levels:
 Aspartate aminotransferase (AST)--- 0-35 IU/L
 Alanine aminotransferase (ALT)--- 0-45 IU/L
 Level correlates with extent of tissue damage.

20. Severe (>20 times, 1000 U/L) :
 Severe viral hepatitis
 Drug or toxin induced necrosis
 Circulatory shock
Moderate (3-20 times) :
 Acute hepatitis
 Neonatal hepatitis
 Chronic hepatitis
 Autoimmune hepatitis
 Drug induced hepatitis
 Alcoholic hepatitis
 Acute biliary tract obstruction

21. Mild (1-3 times) :
 Sepsis induced neonatal hepatitis
 Extrahepatic biliary atresia
 Cirrhosis, Fatty liver
 Non alcoholic steatohepatitis
 Drug toxicity, Myositis
 Duchenne muscular dystrophy, After vigorous exercise
AST:ALT ratio :
 Wilson disease, CLD, ALD : Ratio of >2
 NASH with absence of fibrosis in liver biopsy : Ratio <1
 ALT > AST: Toxic hepatitis, viral hepatitis, chronic active
hepatitis and cholestatic hepatitis

22. Mitochondrial AST : Total AST ratio :
 Characteristically elevated in alcoholic liver
disease and Wilson disease.
False low aminotransferase levels :
 Patients on long term hemolysis.
 Uremia.

23.  Mitochondrial enzyme
 Liver, Heart, Muscle & Kidneys
 In liver highest concentration is seen in centrilobular
hepatocytes
 Normal levels are 0 – 12 IU/L
 Levels elevated in alcoholic hepatitis

24.  Family of zinc metalloenzymes with serine at a
active centre.
 Normal levels are 30 – 120 IU/L
 In liver present on histochemically in the
microvilli of the bile canaliculi and on the
sinusoidal surface of hepatocytes.

25.  Hepatic Isoenzyme – Travels fastest towards the
anode and occupies the same position as α-2
globulin. Its level rises in extra hepatic biliary
obstruction.
 Bone Isoenzyme – Increases die to osteoblastic
activity and is normally elevated in children during
periods of active growth .
 Placental Isoenzyme – Rises during last 6 weeks of
pregnancy.
 Intestinal Isoenzyme – Rise occurs after a fatty
meal. May increase during various GI disorders.

26.  Regan isoenzyme
 Present in plasma of about 15% of patients with
carcinoma of lung, liver or gut
 Also seen in chronic smokers
 Structurally resembles placental ALP
 Nagao Isoenzyme
 Variant of Regan isoenzyme
 Detected in metastatic carcinoma of pleural
surfaces and adenocarcinoma of pancreas and
bile duct.

27.  Physiological
 Women in third trimester of pregnancy
 Adolescents
 Benign, familial (due to increased intestinal ALP)
 Pathological
 Bile duct obstruction
 Primary biliary cirrhosis
 Primary sclerosing cholangitis
 Adult bile ductopenia
 Drug induced cholestasis
 Metastatic liver disease
 Bone disease – Paget’s disease, Hyperparathyroidism

28.  Hepatocytes & Biliary epithelial cells
 Limited due to lack of specificity.
 Large amounts are found in kidneys, pancreas, liver,
intestine and prostate.
 Values higher in neonates and infants upto 1 year and
also increase after 60 year of life.
 Normal range : <55 U/L in males
<38 U/L in females

29.  Hepatobiliary disease
 Pancreatic disease
 Chronic alcoholism
 Chronic obstructive pulmonary disease
 Renal failure
 Diabetes
 Myocardial infarction
 Drugs like carbamazapine, phenytoin, barbiturates
If ALP raise is in parallel to GGT then the elevation is
due to ALD.

30.  This enzyme catalyzes the conversion of 5’
nucleotides to 5’ nucleosides.
 Moderately increased in hepatitis and highly
elevated in biliary obstruction.
 Not a routinely done assay.

31.  Sources are salivary amylase and pancreatic
amylase.
 Normal levels are 80 – 180 somogyi units.
 > 1000 times increase level of amylase are seen in
acute pancreatitis within 24 hours.
 Other conditions where increased serum amylase
levels seen are intestinal obstruction, perforation
ulcer, mumps or parotitis, opiate adminstration.

32.  More specific to pancreatic disorders.
 Normal values are 9 – 20 mIU.
 Moderate elevation is seen in perforated duodenal
& peptic ulcer.
 Elevation of more than 100 times is seen in acute
pancreatitis.