Question

Two of the 20 commonly occurring amino acids contain a sulfur atom. Identify the most direct source of the sulfur atom in these amino acids in humans.

A. Coenzyme
B. A Tetrahydrofolate
C. Biotin
D. Homocysteine
E. glutathione

Answer 1

The answer is D. Homocysteine.

Step-by-step explanation:

Note that homocysteine is one of the sulfur containing acid and closely related to methionine and cysteine. It is formed during the metabolism of the essential amino acid methionine in the methylation cycle.