Isolation of Mitochondrial Succinate: Ubiquinone Reductase, Cytochrome c Reductase and Cytochrome c Oxidase from Neurospora crassa Using Nonionic Detergent

Publisher Website
Google Scholar
Abstract
The electron transfer complexes, succinate: ubiquinone reductase, ubiquinone: cytochrome c reductase and cytochrome c:O2 oxidase were isolated from the mitochondrial membranes of N. crassa by the following steps. Modification of the contents of the complexes in mitochondria by growing cells on chloramphenicol; solubilization of the complexes by Triton X-100; affinity chromatography on immobilized cytochrome c and ion exchange and gel chromatography. Ubiquinone reductase was obtained in a monomeric form (MW .apprxeq. 130,000) consisting of a flavin subunit (MW 72,000) an FeS subunit (MW 28,000) and a cytochrome b subunit (MW probably 14,000). Cytochrome c reductase was obtained in a dimeric form (MW .apprxeq. 550,000), the monomeric unit comprising 2 cytochromes b (MW each 30,000), a cytochrome c1 (MW 31,000), an Fe-S subunit (MW 25,000) and 6 subunits without known prosthetic groups (MW 9000, 11,000, 14,000, 45,000, 45,000 and 52,000). Cytochrome c oxidase was also isolated in a dimeric form (MW .apprxeq. 320,000) comprising 2 copies each of 7 subunits (MW 9000, 12,000, 14,000, 18,000, 21,000 and 40,000). The complexes were essentially free of phospholipid. Each bound 1 micelle of Triton X-100 (MW .apprxeq. 90,000). After isolation, the bound Triton X-100 could be replaced by other nonionic detergents such as: alkylphenyl polyoxyethylene ethers, alkyl polyoxyethylene ethers and acyl polyoxyethylene sorbitan esters.

This publication has 55 references indexed in Scilit: