Nitroxide destruction and flavin-photosensitized damage in inner mitochondrial membranes

Author:

Mehlhorn Rolf Joachim,Packer Lester

Abstract

Nitroxide free radicals lost their paramagnetic absorption spectrum when they were illuminated with visible light in aged but not freshly isolated inner mitochondrial membranes (SMP's). The action spectrum of spin loss rates coincided with a flavin absorption spectrum. Spin loss consisted of one-electron reduction and "destruction", the latter being defined as spin loss that cannot be reversed by ferricyanide oxidation. By placing SMP's in gas permeable tubing and illuminating alternately under nitrogen and air, it was possible to discriminate qualitatively between spin reduction and destruction. Aerobic spin loss consisted entirely of destruction. When aged SMP's were centrifuged, spin loss was observed in supernatants but not pellets. Flavin fluorescence was observed in the supernatants, suggesting that free flavins catalyzed spin loss. However, addition of exogenous flavins to fresh SMP's did not cause spin loss; hence some other factor was required to cause nitroxide destruction. This factor accumulates during either aerobic or anaerobic aging of SMP's and may be present in mitochondria. Supernatants of aged SMP's, when added to freshly isolated SMP's, induced rapid nitroxide destruction, slightly accelerated photodamage to succinate oxidase, and considerably increased photo-induced lipid peroxidation.

Publisher

Canadian Science Publishing

Subject

Organic Chemistry,General Chemistry,Catalysis

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3