Nakamura M, Nakamura S
Research Institute for Electronic Science, Hokkaido University, Sapporo, Japan.
Biochim Biophys Acta. 1996 Apr 17;1289(3):329-35. doi: 10.1016/0304-4165(95)00161-1.
Formation of NO myoglobin through the reaction of horse heart metmyoglobin with NADH in the presence of nitrite was observed optically at pH 5.5. Superoxide generation during the reaction was demonstrated using the ESR spin trap, 5,5-dimethyl-1-pyrroline-1-oxide. A weak optical spectrum corresponding to oxymyoglobin appeared transiently and the spectrum of NO myoglobin then developed. The conversion to NO myoglobin was eliminated in the presence of catalase, SOD or 5,5-dimethyl-1-pyrroline-1-oxide. The kinetics of NADH oxidation and oxygen consumption catalyzed by myoglobin showed an initial lag phase, indicating a chain reaction. When the oxygen was exhausted, the NO form emerged. The duration of the lag phase was prolonged by an increase in the concentration of catalase, SOD or 5,5-dimethyl-1-pyrroline-1-oxide, whereas it disappeared in the presence of H2O2. The spectral change from metmyoglobin to NO myoglobin was also observed under anaerobic conditions though the rate was slower than that obtained under aerobic conditions, while the spectral change was accelerated in the presence of H2O2. Nitric oxide (NO) was derived through the reaction of nitrite with NADH. The formation of NO myoglobin from metmyoglobin is explained in terms of the NADH-oxidase reaction catalyzed by myoglobin. Ascorbate and GSH also serve as reductants though NO myoglobin was formed slowly.
在pH 5.5条件下，通过光学方法观察到马心高铁肌红蛋白在亚硝酸盐存在下与NADH反应生成一氧化氮肌红蛋白。使用ESR自旋捕获剂5,5-二甲基-1-吡咯啉-N-氧化物证明了反应过程中产生超氧化物。对应于氧合肌红蛋白的弱光谱短暂出现，然后一氧化氮肌红蛋白的光谱发展。在过氧化氢酶、超氧化物歧化酶或5,5-二甲基-1-吡咯啉-N-氧化物存在下，向一氧化氮肌红蛋白的转化被消除。肌红蛋白催化的NADH氧化和氧气消耗动力学显示出初始滞后阶段，表明存在链式反应。当氧气耗尽时，一氧化氮形式出现。滞后阶段的持续时间因过氧化氢酶、超氧化物歧化酶或5,5-二甲基-1-吡咯啉-N-氧化物浓度的增加而延长，而在过氧化氢存在下则消失。在厌氧条件下也观察到了从高铁肌红蛋白到一氧化氮肌红蛋白的光谱变化，尽管其速率比有氧条件下慢，而在过氧化氢存在下光谱变化加速。一氧化氮（NO）通过亚硝酸盐与NADH的反应产生。从高铁肌红蛋白形成一氧化氮肌红蛋白可以用肌红蛋白催化的NADH氧化酶反应来解释。抗坏血酸和谷胱甘肽也可作为还原剂，不过一氧化氮肌红蛋白形成得较慢。
