title: Effect of oxygen on the synthesis and assembly of mitochondrial encoded subunits of cytochrome oxidase and cytochrome b.c1 in mouse embryo fibroblasts.
abstract: Mouse embryo fibroblasts were grown in low and control O2 for 24 h (average medium oxygen tensions, 7 torr and 143 torr, respectively). Relative to controls, there was a reduction in radiolabeled subunits in immunoprecipitates of cytochrome oxidase and cytochrome b.c1 prepared from low O2 cells. Incorporation of radiolabeled amino acids into subunit I of cytochrome oxidase and the apocytochrome b protein of the b.c1 complex ranged from 51-100% of control, whereas the appearance of these pulse-labeled subunits into holoenzymes immunoprecipitated from low O2 cells was in the range of 6-39% of control. The synthesis of subunit II of cytochrome oxidase by low O2 cells ranged from 63-100% of control, and assembly of this protein into the low O2 immunoprecipitated enzyme ranged from 15-61% of control. Thus, the data suggest that O2 had an effect on the assembly of these mitochondrially translated proteins that was independent of any effect on their synthesis.
authors.affiliation: Department of Biochemistry and Molecular Biology, Oregon Health Sciences University, Portland 97201.
authors.forename: M A
authors.initials: MA
authors.lastname: Asson-Batres
authors.forename: J F
authors.initials: JF
authors.lastname: Hare
mesh_terms: D000818:Animals; D014450:Electron Transport Complex III / Q000378:metabolism*; D003576:Electron Transport Complex IV / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004622:Embryo, Mammalian / Q000201:enzymology*; D005347:Fibroblasts / Q000201:enzymology; D051379:Mice; D008928:Mitochondria / Q000201:enzymology*; D010100:Oxygen / Q000378:metabolism*; D011233:Precipitin Tests
chemical_list: D003576:Electron Transport Complex IV; D014450:Electron Transport Complex III; D010100:Oxygen