Which vitamin acts as a coenzyme for the enzyme homocysteine methyltransferase, helping to convert homocysteine to methionine?

A Vitamin B6
B Vitamin B9 (Folic acid)
C Vitamin B12 ✓
D Vitamin C

Explanation

Vitamin B12 is necessary for the conversion of homocysteine to methionine through its role as a coenzyme for homocysteine methyltransferase.

Mnemonic

_B12 = Bridge for methionine synthesis

Source

Harper's Biochemistry
Vitamins Biochemistry Amino Acid Metabolism Medium MEDICAL Confidence: high