Which of the following vitamins become a major electron acceptor, aiding in the oxidation of numerous substrates?
A. Vitamin B6B. Niacin
C. Riboflavin
D. Thiamine
Answer. B. Niacin
NAD is the functional coenzyme
derivative of niacin. It is the major electron acceptor in the oxidation of
molecules, generating NADH, which is the major electron donor for reduction
reactions. Thiamine (also known as vitamin B1) occurs functionally as thiamine
pyrophosphale and is a coenzyme for enzymes such as pyruvate dehydrogenase.
Riboflavin (vitamin B2) functions in the coenzyrne forms of FMN or FAD. When
concentrated, both have a yellow color due to the riboflavin they contain. Both
function as prosthetic groups of oxidation- reduction enzymes or flavoproteins.
Flavoproteins are active in selected oxidation reactions and in electron
transport, but they do not have the ubiquitous role of NAD+.
