Question:medium
Which amino acid is used to synthesise Nitric oxide ?
Which amino acid is used to synthesise Nitric oxide ?
Updated On: Jun 23, 2026
- glycine
- arginine
- tyrosine
- threonine
Show Solution
The Correct Option is B
Solution and Explanation
Step 1: Vasodilatory nitric oxide does not appear on its own - it is enzymatically produced by nitric oxide synthases present in neurons, endothelium, and immune cells.
Step 2: The substrate these enzymes act on is the basic amino acid arginine. The reaction strips a nitrogen to yield NO while leaving behind citrulline, and it depends on $O_2$ and $NADPH$ as helpers.
Step 3: Whether it is the nNOS, iNOS, or eNOS isoform, the starting amino acid is always arginine. The remaining options - glycine, tyrosine, threonine - have no role as the NO source.\[\boxed{Arginine}\]
Step 2: The substrate these enzymes act on is the basic amino acid arginine. The reaction strips a nitrogen to yield NO while leaving behind citrulline, and it depends on $O_2$ and $NADPH$ as helpers.
Step 3: Whether it is the nNOS, iNOS, or eNOS isoform, the starting amino acid is always arginine. The remaining options - glycine, tyrosine, threonine - have no role as the NO source.\[\boxed{Arginine}\]
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