Question

(a)What do you understand by the term apoenzyme?
(b)Distinguish between isoenzyme and coenzyme.
(c)Distinguish between apoenzyme and coenzyme.
(d)Differentiate between enzyme and isoenzyme.

Answer 1

(a) Apoenzyme is an inactive enzyme which after binding with organic or inorganic cofactor becomes active (holoenzyme).

(b) Isoenzymes are those enzymes which perform a similar function but varies in structural and biochemical properties, whereas, coenzymes are helper molecules that bind to the enzyme and activates the enzyme. Example of isoenzymes is lactate dehydrogenase (LDH) and of coenzyme is thiamine pyrophosphate (TPP).

(c) Apoenzyme is an inactive enzyme which after binding with organic or inorganic cofactor becomes active (holoenzyme) and on the other hand, coenzymes are helper molecules that bind to apoenzyme and activates the apoenzyme. Example of apoenzyme is aspartate transcarbamoylase and of coenzyme is thiamine pyrophosphate (TPP).

(d) An enzyme is a globular protein that catalyzes a biological chemical reaction. It accelerates the rate of reaction. Whereas, isoenzymes are those enzymes which perform a similar function but varies in structural and biochemical properties. Example of isoenzymes is lactate dehydrogenase (LDH) and of an enzyme is DNA polymerase.