Identification and characterization of nitric oxide synthase inSalmonella typhimurium
The presence of the nitric oxide synthase (NOS) enzyme fromSalmonella typhimurium (S. typhimurium) was identified by measuring radiolabeled L-[3H]citrulline and NO, and Western blot analysis. NOS was partially purified by both Mono Q ion exchange and Superose 12HR size exclusion column chromatography, sequentially. The molecular weight of NOS was estimated to be 93.3 kDa by Western blot analysis. The enzyme showed a significant dependency on the typical NOS cofactors; an apparent Km for L-arginine of 34.7 mM and maximum activity between 37°C and 43°C. The activity was inhibited by NOS inhibitors such as aminoguanidine and NG,NG-dimethyl-L-arginine. Taken together, partially purified NOS inS. typhimurium is assumed to be a different isoform of mammalian NOSs.
Key wordsSalmonella typhimurium Nitric oxide Nitric oxide synthase
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