Lobysheva I I, Serezhenkov V A, Vanin A F
Institute of Chemical Physics, Russian Academy of Sciences, Moscow, 117977, Russia.
Biochemistry (Mosc). 1999 Feb;64(2):153-8.
The interaction of peroxynitrite with thiolate dinitrosyl iron complexes (DNIC) has been examined and compared with the interaction with H2O2. Peroxynitrite oxidized DNIC containing various thiolate ligands--cysteine, glutathione, and bovine serum albumin. Analysis of the oxidation suggested a two-electron reaction and gave third-order rate constants of (9.3 +/- 0.5).109 M-2.sec-1 for DNIC with BSA, (4.0 +/- 0.3).108 M-2.sec-1 for DNIC with cysteine, and (1. 8 +/- 0.3).107 M-2.sec-1 for DNIC with glutathione at 20 degrees C and pH 7.6. Peroxynitrite was more reactive towards DNIC than towards sulfhydryls. Addition of sodium dithionite after the reaction led to significant restoration of the EPR signal of DNIC with cysteine. The reaction of glutathione DNIC with H2O2 was about 600 times slower than with ONOO- and not reversed by sodium dithionite. Thus peroxynitrite, in contrast to hydrogen peroxide, changes the pool of nitrosocompounds which can be responsible for interconversion, storage, and transportation of nitric oxide in vivo.
已对过氧亚硝酸盐与硫醇盐二亚硝基铁配合物（DNIC）的相互作用进行了研究，并与它和过氧化氢的相互作用进行了比较。过氧亚硝酸盐可氧化含有各种硫醇盐配体（半胱氨酸、谷胱甘肽和牛血清白蛋白）的DNIC。氧化分析表明这是一个双电子反应，在20℃和pH 7.6条件下，与牛血清白蛋白的DNIC的三阶速率常数为(9.3±0.5)×10⁹ M⁻²·s⁻¹，与半胱氨酸的DNIC为(4.0±0.3)×10⁸ M⁻²·s⁻¹，与谷胱甘肽的DNIC为(1.8±0.3)×10⁷ M⁻²·s⁻¹。过氧亚硝酸盐对DNIC的反应性比对巯基的反应性更强。反应后加入连二亚硫酸钠可使与半胱氨酸的DNIC的电子顺磁共振信号显著恢复。谷胱甘肽DNIC与过氧化氢的反应比与过氧亚硝酸盐的反应慢约600倍，且连二亚硫酸钠不能使其逆转。因此，与过氧化氢不同，过氧亚硝酸盐会改变亚硝基化合物库，而这些化合物可能在体内负责一氧化氮的相互转化、储存和运输。
