Denitration of peroxynitrite‐treated proteins by “protein nitratases” from dog prostate

10.1080/15216549900202183.absPutative “protein nitratases,” which catalyze denitration of peroxynitrite (PN)‐treated proteins, were detected in the crude extract of dog prostate. Nitratase activity was monitored by the decreased intensity of nitrotyrosine immunoreactive‐bands in Western blot and increased nitrate level in dialysate of incubation mixture, which contained prostate crude extract, protease inhibitors and a PN‐treated substrate, such as treated histone (III‐S), BSA, invertase, or polylysine. Nitratases were activated by preincubation with m‐calpain/Ca2+. Furthermore, after denitration, the activity of PN/DTT‐treated invertase decreased to the similar activity level of DTT‐treated invertase. At least two different types of nitratases may occur: type I, reductant‐dependent, and type II, reductant‐independent.