Amino Acids, Proteins and Porphyrins
ADH requires NAD+ for catalytic activity. In the reaction catalyzed by ADH, an alcohol is oxidized to an aldehyde as NAD+ is reduced to NADH and dissociates from the enzyme. The NAD+ is functioning as a (an):
a. Coenzymes-cosubstrates are small organic molecules that associate transiently with an enzyme and leave the enzyme in a changed form.
b. Coenzyme-prosthetic groups are small organic molecules that associate permanently with an enzyme and are returned to their original form by the enzyme.
c. Cofactors are metal ions. Heterotropic effectors are not substrates.