Kunák Michal, Kucera Igor, van Spanning Rob J M
Department of Biochemistry, Faculty of Science, Masaryk University, Kotlárská 2, CZ-61137 Brno, Czech Republic.
Arch Biochem Biophys. 2004 Sep 15;429(2):237-43. doi: 10.1016/j.abb.2004.06.026.
Nitric oxide is a denitrification intermediate which is produced from nitrite and then further converted via nitrous oxide to nitrogen. Here, the effect of low concentrations of the protonophore carbonylcyanide m-chlorophenylhydrazone on the time courses for dissolved gases was examined. While NO was found to oscillate, N(2)O only increased gradually as the reduction of nitrite progressed. The frequency and shape of protonophore-induced NO oscillations were influenced by temperature and the concentration of electron donor N,N,N',N'-tetramethyl-p-phenylene diamine (TMPD) in a manner compatible with the observed differential effects on the two involved enzyme activities. We demonstrated the existence of a pH interval, where [NO] oscillates even without uncoupler addition. Occurrence of nitric oxide oscillations in mixtures of a nitrite reductase mutant with a nitric oxide reductase mutant suggests that they cannot be due to a competition of the enzymes for redox equivalents from one common respiratory chain.
一氧化氮是反硝化作用的中间产物，它由亚硝酸盐产生，然后通过一氧化二氮进一步转化为氮气。在此，研究了低浓度质子载体羰基氰化物间氯苯腙对溶解气体时间进程的影响。虽然发现一氧化氮会振荡，但随着亚硝酸盐还原的进行，一氧化二氮只是逐渐增加。质子载体诱导的一氧化氮振荡的频率和形状受温度和电子供体N,N,N',N'-四甲基对苯二胺（TMPD）浓度的影响，其方式与观察到的对两种相关酶活性的差异效应一致。我们证明了存在一个pH区间，即使不添加解偶联剂，[NO]也会振荡。亚硝酸还原酶突变体与一氧化氮还原酶突变体混合物中一氧化氮振荡的出现表明，它们并非由于酶对来自一个共同呼吸链的氧化还原当量的竞争所致。
