真菌醌类色素作为线粒体NADH：泛醌还原酶的氧化剂和抑制剂

Fungal quinone pigments as oxidizers and inhibitors of mitochondrial NADH:ubiquinone reductase.

作者信息

Bironaité D A, Cénas N K, Anusevicius Z J, Medentsev A G, Akimenko V K, Usanov S A

机构信息

Institute of Biochemistry, Lithuanian Academy of Sciences, Mokslininku.

出版信息

Arch Biochem Biophys. 1992 Sep;297(2):253-7. doi: 10.1016/0003-9861(92)90669-n.

DOI:10.1016/0003-9861(92)90669-n

PMID:1497345

Abstract

The interaction of fungal quinone pigments bostricoidin, fusarubin, javanicin, and 2-oxyjuglone with mitochondrial NADH:ubiquinone reductase (complex I, EC 1.6.99.3) has been studied. The bimolecular rate constants (turnover number (TN)/Km) of rotenone-insensitive reduction of these compounds are in the range of 1.2 x 10(4)-1.6 x 10(5) M-1s-1. 2-Oxyjuglone acts as inhibitor of NADH:ferricyanide reductase reaction of complex I (KI = 30 microM). All quinone pigments, except javanicin, decrease the TN of reduction of 5,8-dioxy-1,4-naphtoquinone being reduced at its binding site but with significantly lower TN. They do not affect the rotenone-sensitive reduction of ubiquinone-1. The binding of quinone pigments close to the NADH and ferricyanide binding site is suggested. It seems that quinone pigments, especially 2-oxyjuglone, react with complex I faster than it follows from their approximate values of one-electron reduction potential calculated from their reactivities with flavocychrome b2 and adrenodoxin.

摘要

已对真菌醌类色素波斯特里菌素、镰孢菌素、爪哇菌素和2-氧代胡桃醌与线粒体NADH：泛醌还原酶（复合体I，EC 1.6.99.3）的相互作用进行了研究。这些化合物对鱼藤酮不敏感的还原反应的双分子速率常数（转换数（TN）/Km）在1.2×10⁴ - 1.6×10⁵ M⁻¹s⁻¹范围内。2-氧代胡桃醌作为复合体I的NADH：铁氰化物还原反应的抑制剂（抑制常数KI = 30 μM）。除爪哇菌素外，所有醌类色素都会降低在其结合位点被还原的5,8-二氧基-1,4-萘醌的还原转换数，但转换数显著更低。它们不影响泛醌-1对鱼藤酮敏感的还原反应。推测醌类色素在靠近NADH和铁氰化物结合位点处结合。似乎醌类色素，尤其是2-氧代胡桃醌，与复合体I的反应速度比根据它们与黄素细胞色素b2和肾上腺皮质铁氧化还原蛋白反应性计算出的单电子还原电位近似值所预期的要快。