Dual Effects of the Substrate and Pterins on the Kinetics of CO Binding to Neuronal Nitric Oxide Synthase:A Laser Flash Photolysis Study

摘要

Derivatives of pterin,an important cofactor for neuronal nitric oxide synthase,markedly changed the kinetics of CO binding to the enzyme-bound heme.In the absence of the substrate,L-Arg,CO binding was dependent on the CO concentration for pterin complexes,whereas in the presence of L-Arg,it became CO-independent for most pterin complexes.This suggests dual effects of substrate and pterin binding on the kinetics and access of CO to the ligand channel.