Which amino acid is the precursor for the synthesis of nitric oxide in the body?

A Arginine ✓
B Glutamine
C Aspartic acid
D Lysine

Explanation

Arginine is converted to citrulline and nitric oxide by the enzyme nitric oxide synthase, playing a crucial role in vascular relaxation and immune function.

Mnemonic

'Arg' = 'argument' for nitric oxide production

Source

Nelson et al., Lehninger Principles of Biochemistry
Protein Metabolism Biochemistry Amino Acid Metabolism Hard MEDICAL Confidence: high