Biochemistry Proteins and Amino Acids 681c79ab Methionine is synthesised in human body from - A Cysteine B Homocysteine C Cystine D Tryptophan High-Yield Explanation Ans. is 'b' i.e., Homocysteine* Homocysteine in the presence of methionine synthase and methyl B12, gets converted to methionine.