Nitric oxide is synthesized from which amino acid:-
Nitric oxide is synthesized from Arginine Amino Acid, and Arginine is formed in urea cycle by the help of argino- succinate lyase Synthase usually belongs to EC number 4, except NO synthase which has EC number 1 because it belongs to oxidoreductase category NO synthase is Mono oxygenase, i.e. only oxygen added at substrate SERINE Serine is a non-essential glycogenic amino acid. Serine and glycine are interconveible Serine can be Synthesized from the intermediates of glycolysis (3-phosphoglycerate) 1. Serine paicipates in transamination reactions. It undergoes deamination to form pyruvate. 2. Serine is involved in one-carbon metabolism. It donates methylene(-CH2) moiety to tetrahydrofolate (THF). 3. Serine is utilized for the synthesis of cysteine. It may be noted that the entire cysteine molecule is derived from serine except the sulphur that comes from homocysteine 4. Serine is involved in the formation of selenocysteine, the 21st amino acid found in ceain proteins. 5. Serine is also involved in the synthesis of sphingomyelins and cephalins. THREONINE Threonine is an essential hydroxy amino acid. It is glycogenic and does not paicipate in transamination reactions. Threonine undergoes deamination (by threonine dehydratase to a-ketobutyrate which is conveed to propionyl CoA. Threonine can be cleaved to glycine and acetaldehyde by serine hydroxymethyl transferase. Dehydrogenation followed by decarboxylation of threonine result in aminoacetone which may be conveed to pyruvate or lactate. Lysine Lysine is an essential amino acid. Lysine is a ketogenic amino acid. Cereal proteins are deficient in lysine. It does not paicipate in transamination reactions. Some of the lysine residues in protein structure are present as hydroxylysine, methyllysine or acetyllysine, these derivatives can be hydrolysed to liberate free lysine.
Arginine
Serine
Threonine
Lysine
NEET 2018