The rat neuronal nitric oxide synthase (nNOS) cDNA was expressed in Sa
ccharomyces cerevisiae under the control of a hybrid PGK/GAL promoter,
PAL. Galactose induction resulted in the production of a soluble 160
kDa protein that was recognised by anti-neuronal NOS antibody. NOS act
ivity was detected by the conversion of [H-3]arginine to [H-3]citrulli
ne and required the addition of the cofactors, calmodulin and tetrahyd
robiopterin. The activity was inhibited by the arginine analogues N-G-
nitro-L-arginine and N-G-nitro-L-arginine methyl ester.