試題詳解

42. The primary source of one-carbon units for tetrahydrofolate in the cells is the carbon removed in the conversion of to homocystein.
(A) methionine to homocystein.
(B) serine to pyruvate.
(C) N-methyltetrahydrofolate to tetrahydrofolate.
(D) serine to glycine.
(E) S-adenosylmethionine to S-adenosylhomocystein.