氧自由基对肌纤维中肌球蛋白的影响。

Effect of oxygen free radicals on myosin in muscle fibres.

作者信息

Könczöl F, Lorinczy D, Belagyi J

机构信息

Institute of Forensic Medicine, University Medical School, Pécs, Hungary.

出版信息

FEBS Lett. 1998 May 15;427(3):341-4. doi: 10.1016/s0014-5793(98)00439-6.

DOI:10.1016/s0014-5793(98)00439-6

PMID:9637253

Abstract

Experiments were performed on glycerol-extracted muscle fibres prepared from psoas muscle of rabbit in the presence of hydroxyl free radical generating system. Short irradiation of spin-labelled muscle fibres by UV light showed the interaction of probe molecules with oxygen free radicals. The intensity of the EPR signal from maleimide or isothiocyanate spin labels attached to the essential thiol groups decreased following irradiation. Oxygen free radicals affected the rate constant of the transition AM.ADP.Vi-->AM.ADP in the ATP hydrolysis cycle. It was found that the essential -SH groups of myosin were involved in the oxidation of sulphydryls by Ce(IV). Ce(IV) complexed to nitrilotriacetic acid in the presence of spin trap produced long-lived free radicals located partly on SH-1 sulphydryls.

摘要

在存在羟基自由基生成系统的情况下，对从兔腰大肌制备的甘油提取肌纤维进行了实验。用紫外线对自旋标记的肌纤维进行短时间照射，结果显示探针分子与氧自由基发生了相互作用。照射后，附着在必需巯基上的马来酰亚胺或异硫氰酸酯自旋标记物的电子顺磁共振（EPR）信号强度降低。氧自由基影响了ATP水解循环中AM.ADP.Vi→AM.ADP转变的速率常数。研究发现，肌球蛋白的必需巯基参与了铈（IV）对巯基的氧化。在自旋捕集剂存在的情况下，铈（IV）与次氮基三乙酸络合，产生了部分位于SH-1巯基上的长寿命自由基。