L-arginine analogs as alternate substrates for nitric oxide synthase

The L-arginine analogs, N(delta)-methyl-L-arginine (deltaMA) and L-canavanine, were used to probe the role of the N delta nitrogen of L-arginine in the reaction catalyzed by nitric oxide synthase (NOS). deltaMA was synthesized and found to be a partial alternate substrate and a weak, reversible inhibitor of NOS with a Ki equal to 1.4 mM. deltaMA undergoes hydroxylation; however, it is not converted further, hence it functions as a partial substrate. L-Canavanine was converted to an L-homoserine presumably via initial hydroxylation and decomposition. The mechanism of this reaction and products of this reaction were not probed further.