Competitive inhibition of nitric oxide synthase by p-aminobenzamidine, a serine proteinase inhibitor.
p-Aminobenzamidine competitively inhibits bovine trypsin, human and bovine thrombin, and human plasmin, all of which act on substrates containing preferentially the L-arginyl side chain at their P1 position. Considering the structural and functional similarity between p-aminobenzamidine and the L-arginyl side chain in trypsin-like serine proteinases, we investigated the interaction of p-aminobenzamidine with mouse brain nitric oxide synthase (NOS), which uses L-arginine as the substrate for generating NO and L-citrulline. p-Aminobenzamidine is a competitive NOS inhibitor (Ki = 1.2 x 10(-4) M, at pH 7.5 and 37.0 degrees C), but not an NO precursor. Therefore, p-aminobenzamidine affects the NO production and the trypsin-like serine proteinase action.
Venturini
G
G
Department of Biology, Third University of Rome, Italy.
Menegatti
E
E
Ascenzi
P
P
D000818:Animals; D001550:Benzamidines / Q000494:pharmacology*; D001667:Binding, Competitive; D008297:Male; D051379:Mice; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology*
D001550:Benzamidines; D015842:Serine Proteinase Inhibitors; C006500:4-aminobenzamidine; D019001:Nitric Oxide Synthase