Khramtsov V V, Grigor'ev I A, Kiriljuk I A, Utepbergenov D I
Institute of Molecular Pathology & Environmental Biochemistry, Novosibirsk State University, Russia.
Biochem Biophys Res Commun. 1994 Jul 15;202(1):195-203. doi: 10.1006/bbrc.1994.1912.
Nitric oxide (NO) has been shown to be an important mediator in vasodilation, neurotransmission and cellular cytotoxicity. We investigated a new series of nitronylnitroxyl radicals (NNR) as spin traps for NO. It was found these radicals react with NO with rate constants of about 10(4) M-1c-1 forming stable iminonitroxides with dramatic changes in EPR spectra. To overcome fast reduction of the radicals (a few seconds in rat cerebella cytosol), NNR with charged trimethylammoniophenyl group (Ib) was incorporated into the inner volume of large unilamellar phosphatidylcholine liposomes. In this case the reduction of the radical Ib in rat cerebella cytosol is slow (ca. 1% per min). The rate of NO production by NO synthase from rat cerebellum measured by NNR, Ib, is in a reasonable agreement with that obtained by spectrophotometric method.
一氧化氮（NO）已被证明是血管舒张、神经传递和细胞毒性中的重要介质。我们研究了一系列新型硝酮硝酰自由基（NNR）作为NO的自旋捕获剂。发现这些自由基与NO反应的速率常数约为10(4) M-1c-1，形成稳定的亚氨基硝酰自由基，其电子顺磁共振光谱发生显著变化。为了克服自由基的快速还原（在大鼠小脑细胞质中几秒钟），将带有带电荷三甲基铵苯基的NNR（Ib）掺入大单层磷脂酰胆碱脂质体的内部体积中。在这种情况下，大鼠小脑细胞质中自由基Ib的还原很慢（约每分钟1%）。通过NNR Ib测量的大鼠小脑一氧化氮合酶产生NO的速率与通过分光光度法获得的速率合理一致。
