The family of nitric oxide synthases (NOS) catalyzes the conversion of l-arginine to l-citrulline and nitric oxide (NO), an important cellular messenger molecule which has been implicated in the pathophysiology of septic shock and inflammatory and neurodegenerative disease states. NOS can be maximally activated by the ubiquitous cofactor,(6 R)-5, 6, 7, 8- tetrahydrobiopterin (H4Bip), and antagonists of H4Bip may be of therapeutic importance to ...