<prompt> Which of the following vitamin acts as a cofactor for metabolism of sulphur containing amino acids?Folic acidBiotinVit KPyridoxine  <response>: Methyl group in N5-methyl tetrahydrofolic acid N5- methyl THFA is used for synthesis of active methionine, which takes pa in transmethylation reactions. Such transmethylation reactions are required for synthesis of choline, epinephrine, creatine etc. Sulphur containing amino acids include cysteine and methionine. Ref: Textbook of Biochemistry by DM Vasudevan, 5th edition, Page 303. 