Reconstitution of the second step in NO synthesis using the isolated oxygenase and reductase domains of macrophage NO synthase

The reductase and oxidase domains of inducible macrophage NO synthase catalyze only the second step of NO synthesis. The interaction involves the transfer of one electron from the reductase to the oxidase domain. These domains can only catalyze the formation of NO from the intermediate N(super omega)-hydroxy-L-arginine. These domains are most active when the amount of oxygenase present is four times that of reductase. The inability of these domains to catalyze the complete NO synthesis is probably due to incomplete electron transfer between these domains.