Lecture 8

Question 1

What is the difference between a coenzyme and cofactor?

Answer 1

A co-enzyme is a small organic non-protein molecule that carries chemical groups between enzymes while a co-factor is a non-protein chemical compound that is bound tightly to an enzyme and is required for catalysis.

Question 2

What is the difference between a competitive inhibitor, uncompetitive inhibitor, & a noncompetitive inhibitor?

Answer 2

A competitive inhibitor directly binds to an enzyme before a substrate can, disallowing an enzyme-substrate complex from forming. A noncompetitive inhibitor directly binds to an enzyme-substrate complex, disallowing a product to be formed. A uncompetitive inhibitor can do either of the above functions.

Question 3

A homotropic effector is ______ while a hetertropic effector is ______.

Answer 3

Positive; negative

Question 4

What is an isozyme?

Answer 4

Isozymes are enzymes that differ in amino acid sequence but catalyze the same chemical reaction. These enzymes usually display different kinetic parameters, or different regulatory properties.

Question 5

The steeper the slope of a lineweaver-burk plot, the _____ the affinity of a substrate for enzyme

Answer 5

Lower

Question 6

What is the relationship between Vmax and the concentration of active enzyme?

Answer 6

They are directly proportional. As Vmax decreases, so does the concentration of active enzyme. As Vmax increases, so does the concentration of active enzyme.