Nitric oxide synthase, inducible (iNOS) (iNOS)

Inducible nitric oxide synthase (iNOS), also known as NOS2, is a key enzyme in the inflammatory response that produces high levels of nitric oxide (NO) from the amino acid L-arginine [1][5]. Unlike the constitutive isoforms (nNOS and eNOS), iNOS is typically expressed only after induction by proinflammatory cytokines or bacterial lipopolysaccharides, and its activity is independent of intracellular calcium levels [3][4]. The NO produced by iNOS plays a critical role in host defense by acting as a cytotoxic agent against pathogens and tumor cells; however, its chronic overproduction is linked to tissue damage in diseases such as sepsis, asthma, and rheumatoid arthritis [2][6]. Therapeutic strategies targeting iNOS include the development of small-molecule inhibitors that selectively bind to the enzyme active site or agents that prevent its transcriptional upregulation [7]. A major challenge in drug development is achieving high selectivity for iNOS over other isoforms to avoid adverse effects like hypertension or impaired neurotransmission [8]. Clinical trials have explored iNOS inhibitors for conditions like septic shock and chronic inflammatory airway diseases, though many have faced challenges regarding efficacy and safety profiles [4][8].

Other names

NOS2Nitric oxide synthase 2NOS-IIHepatocyte NOSiNOS

Competitive inhibition of the L-arginine binding site or suppression of transcriptional induction via NF-kappaB inhibition [3][4].