Homocystinuria is caused by deficiency of
High-Yield Explanation
PLP is the coenzyme for many reactions if amino acids containing sulphur. PLP plays an impoant role in methionine and cysteine metabolism. Homocysteine + Serine - Cystathionine. (Enzyme Cystathionine synthase) Cystathionine - Homoserine + Cysteine (Enzyme Cystathionase) Both these reactions require PLP. Hence in vitamin, B6 deficiency homocysteine in the blood is increased. Homocysteine level is correlated with myocardial infarction. Therefore, pyridoxine is used to prevent homocysteinemia. Ref: DM Vasudevan - Textbook of Biochemistry, 8th edition, page no: 471