L-glutamine is an optically active form of glutamine having L-configuration. It has a role as an EC 1.14.13.39 (nitric oxide synthase) inhibitor, a nutraceutical, a micronutrient, a human metabolite, a Saccharomyces cerevisiae metabolite, an Escherichia coli metabolite and a mouse metabolite. It is a glutamine family amino acid, a proteinogenic amino acid, a glutamine and a L-alpha-amino acid. It is a conjugate base of a L-glutaminium. It is a conjugate acid of a L-glutaminate. It is an enantiomer of a D-glutamine. It is a tautomer of a L-glutamine zwitterion.