Inhibition of Rat Liver Arginase by an Intermediate in NO Biosynthesis, NG-Hydroxy-L-arginine: Implications for the Regulation of Nitric Oxide Biosynthesis by Arginase

摘要: NG-hydroxy-L-arginine, an intermediate in the biosynthesis of nitric oxide (NO), has been found to be a uniquely potent competitive inhibitor rat liver arginase. Among previously reported inhibitors arginase and eight arginine analogs tested herein, only NG-hydroxy-L-arginine was strongly inhibitory. Significantly, Ki (42 microM) for inhibition by 20-40-fold lower than KM (1-1.7 mM) its natural substrate, L-arginine. Since is known NO from L-arginine, this finding may have significant implications regulation levels tissues or cells, such as macrophages, which synthesize both contain