Clinical Chemistry 2: Enzyme Kinetics

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What is the primary advantage of measuring the increase in product rather than the decrease in substrate in enzyme reactions?

The increase in product is a direct measure of enzyme activity
The decrease in substrate is a slower process
It is easier to measure the increase in product (correct)
It is easier to measure the decrease in substrate

What is the effect of increasing the ionic strength of a solution on enzyme activity?

It depends on the type of enzyme
It has no effect on the enzyme activity
It increases the enzyme activity
It decreases the enzyme activity (correct)

Which of the following is NOT a suitable anticoagulant for measuring enzyme activity in a blood sample?

EDTA (correct)
Citrate
Heparin
Oxalate

What is the effect of a 10°C increase in temperature on enzyme activity?

It causes a doubling of enzyme activity (D) Signup and view all the answers

What type of enzyme inhibitor competes with the substrate for binding to the active site of the enzyme?

Competitive inhibitor (B) Signup and view all the answers

What is the pH range in which most enzyme reactions occur?

pH 7-8 (C) Signup and view all the answers

What type of inhibitor binds to an enzyme different from the catalytic site, removing cofactors in the process?

Non-competitive inhibitor (A) Signup and view all the answers

Which class of enzyme catalyzes the transfer of a group, other than hydrogen, from one substrate to another?

Transferase (D) Signup and view all the answers

What is the purpose of the last number in the Enzyme Commission of the International Union of Biochemistry standardized designation?

To indicate the specific number given to each enzyme in its sub-subclass (A) Signup and view all the answers

What type of enzyme catalyzes the removal of groups from substrates without hydrolysis, resulting in a double bond product?

Lyase (C) Signup and view all the answers

What is the function of an uncompetitive inhibitor?

To bind to the E-S complex and prevent dissociation (C) Signup and view all the answers

What is the primary function of ligase enzymes?

To catalyze the joining of two substrate molecules coupled with the breaking of a pyrophosphate bond (A) Signup and view all the answers

What is the primary advantage of using Alanine Aminotransferase (ALT) over Aspartate Aminotransferase (AST) in diagnosing liver disease?

ALT is more specific to liver disease (B) Signup and view all the answers

Which of the following methods is used to detect Alanine Aminotransferase (ALT) activity?

Reitman-Frankel method (B) Signup and view all the answers

What is the main difference between the substrate used in the Bodansky method and the Shinowara Jones method?

One uses beta-gycerolPO4, while the other uses beta-glyceroPO4 (B) Signup and view all the answers

Why do ALT elevations tend to remain longer than AST elevations in acute inflammatory conditions of the liver?

ALT has a longer half-life in serum (B) Signup and view all the answers

What is the primary concern when measuring ALT activity in patients with viral hepatitis?

Hemolysis of red blood cells (D) Signup and view all the answers

Which of the following is a characteristic of AST that distinguishes it from ALT?

Higher concentration in heart (B) Signup and view all the answers

What is the effect on reaction speed when the substrate concentration is doubled in a first-order reaction?

The reaction speed is doubled (A) Signup and view all the answers

Which type of inhibitor binds to the active site of the enzyme?

Competitive inhibitor (C) Signup and view all the answers

What is the unit of enzyme activity that represents the amount of enzyme needed to catalyze the conversion of 1 mole of substrate to products per second?

Katal (C) Signup and view all the answers

What is the conversion rate of 1 IU to kat?

1 IU = 16.7 kat (C) Signup and view all the answers

What is the method of measuring enzyme activity that involves measuring the rate of disappearance of substrate per unit time?

Measuring the rate of disappearance of substrate per unit time (B) Signup and view all the answers

What is the term for the substrate that is acted upon by the enzyme and is incubated with enzymes present in the patient's serum?

Substrate (B) Signup and view all the answers

What is the primary reason for separating serum from clot quickly in LD isoenzyme measurement?

To prevent increase in LD1 and LD2 (C) Signup and view all the answers

In which condition is a flipped pattern of LD1 > LD2 typically observed?

Cardiac necrosis (B) Signup and view all the answers

What is the primary isoenzyme fraction in the sera of healthy individuals?

LD2 (D) Signup and view all the answers

Which of the following isoenzymes is NOT typically used to test liver disorders?

LD3 (C) Signup and view all the answers

What is the primary reason for avoiding hemolysis in LD isoenzyme measurement?

To prevent LD1 and LD2 elevation (C) Signup and view all the answers

What is the primary characteristic of LD5 isoenzyme in terms of temperature?

Cold-labile (D) Signup and view all the answers

Increase in product measurement

Easier method to measure enzyme reactions than substrate decrease.

Ionic strength effect

Increasing ionic strength decreases enzyme activity.