IDENTIFICATION OF NITRIC-OXIDE SYNTHASE IN STAPHYLOCOCCUS-AUREUS

The presence of nitric oxide synthase (NOS) in Staphylococcus aureus A TCC6538P was established by western blot analysis. The identity of cit rulline formed from L-arginine by the NOS was confirmed by both TLC an d HPLC and the other product, NO, by directly measuring the production of nitrogen oxides (NOx) in the reaction mixture. The activity was in hibited by typical NOS inhibitors such as N-nitro-L-arginine methylest er and NG,NG-dimethyl-L-arginine with the IC50 of 4.9 x 10(-4) and 2.5 x 10(-4) M, respectively. The NOS activity was maximum at pH 6.5 and at 47.5 degrees C. These results indicate that the NOS of S. aureus AT CC6538P is an isoform distinct from mammalian NOS. (C) 1997 Academic P ress.