11 Questions
What is the type of reaction that measures the rate disappearance of starch substrate?
Amyloclastic
Which enzyme is most widely accepted for use in GGT analysis?
Y-Glutamyl Transferase
Which enzyme has a peak seen about 24 hours after the first 8 hours in acute pancreatitis?
CK-MM
In what disorder is Lactate Dehydrogenase LD1 (HHHH) elevated?
Myocardial Infarction
Which enzyme is considered the richest source of Acid Phosphatase in the prostatic gland?
Acid Phosphatase
Which substrate is used in the reverse reaction?
Olive oil
In which method is olive oil used as a substrate?
Cherry crandal Method
At what pH is the Cherry crandal Method performed?
Acidic
Which method uses phenyl phosphate as a substrate?
King Armstrong Method
What is the conventional conversion factor for ALANINE AMINOTRANSFERASE in SI units?
55-170 u/L
Which method is used for ALT, utilizing Dinitrophenylhydrozyl (DNPH) as a chromogen?
Rietmann Frankel Method
Study Notes
Enzyme Assays and Reactions
- The substrate used in reverse reaction is pyruvate.
- The reaction is faster if the reverse reaction is used.
Titration Methods
- Titrimetric method is used.
- Turbidimetric method is mostly used, less time-consuming, and observes turbidity.
- Olive oil is used as a substrate, which is hydrolyzed by lipase.
Lipase Assays
- Cherry crandal method is a classic method for lipase, utilizing olive oil as a substrate.
- Same as ALP, but performed at an acidic pH.
- Bowers and Mc Comb method uses β-glycerol phosphate as a substrate.
- King Armstrong method uses phenyl phosphate.
Conventional Conversion Factors and Units
- 16-120 Somogyi units/dL is equivalent to 1.85 U/L.
- 30-220 U/L is equivalent to 55-170 U/L for males and 30-135 U/L for females.
- 1200-2000 μ/mL packed erythrocytes is equivalent to 5-40 U/L.
Lactate Dehydrogenase (LDH)
- 100-190 U/L at 37°C.
- LDH has 5 isoenzymes: LD1, LD2, LD3, LD4, and LD5.
Other Enzymes
- Leucine aminopeptidase: 80-200 U/mL for males and 75-180 U/mL for females.
- 5’ nucleotidase: 0-1.6 units at 37°C.
- Aspartate aminotransferase: 4-36 U/L at 37°C.
- Alanine aminotransferase: 20-130 U/L at 37°C.
Enzyme Isoenzymes and Diseases
- Creatine kinase: CK1 (CKBB), CK2 (CKMB), and CK3 (CKMM); associated with myocardial infarction and skeletal muscle disorder.
- Amylase: associated with acute pancreatitis.
- Glucose-6-phosphate dehydrogenase: associated with drug-induced hemolytic anemia.
- Y-glutamyl transferase: associated with hepatic disorder.
Types of Reactions
- Amyloclastic: measures the rate of disappearance of starch substrate.
- Saccharogenic: measures the appearance of the product.
- Chromogenic: measures the increasing color from product formation.
- Continuous monitoring: coupling of several enzyme systems to monitor amylase activity.
Test your knowledge on enzyme isoenzymes such as amylase, creatine kinase, glucose-6-phosphate dehydrogenase, and more, and their associations with diseases like acute pancreatitis, myocardial infarction, skeletal muscle disorders, and drug-induced hemolytic anemia. Explore the types of reactions involved in enzyme activity and their diagnostic significance.
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