Homocysteine is: (A) Amino-acid in Protein- D form, (B) Amino-acid in Protein- L form, (C) Non-protein alpha amino-acid, (D) Seen in Collagen
Answer is C. Homocysteine is a non-proteinogenic alpha- amino acid Homologous to cysteine, differing by an additional methylene bridge (-CH2-) Synthesized from methionine.