Which of the following are the sulfur containing amino acids? i. Methionine ii. Histidine iii. Leucine iv. Cysteine
Which of the following are the sulfur containing amino acids?i. Methionineii. Histidineiii. Leucineiv. Cysteine
Select an option to attempt
Correct Answer: Option B
Explanation
Sulfur-containing amino acids:Among the 20 standard amino acids, only two contain sulfur:1. Methionine (Met, M): Contains a thioether group () in its side chain. It is the universal start amino acid.2. Cysteine (Cys, C): Contains a thiol group () in its side chain. Can form disulfide bonds () with another Cys, important for protein tertiary structure.Amino acids without sulfur:• Histidine: Contains an imidazole ring (N-containing); no sulfur.• Leucine: A branched-chain aliphatic amino acid with only C, H; no sulfur.Answer: Methionine and Cysteine (the option containing Met/Cys).