title: Respiration-deficient Chinese hamster cell mutants: biochemical characterization.
abstract: We have previously classified 35 of our respiration-deficient mutants into seven complementation groups and one "overlapping" mutant which does not complement mutants from groups I and II. In this paper we report on the biochemical characterization of representatives of complementation groups I, II, VII, and the "overlapping" mutant. We show that these mutants all have a defect in complex I of the electron-transport chain. The general features of these mutants are: (1) a low rate of O2 consumption in whole cells; (2) a low rate of release of 14CO2 from [2-14C] pyruvate, [1-14C] pyruvate, and [3-14C] beta-hydroxybutyrate; (3) a low rate of release of 14CO2 from [5-14C] glutamate and [1-14C] glutamate in mutants from groups II, VII, and the "overlapping" mutant, whereas a significant amount of 14CO2 is released in mutants from group I; (4) a substantial rate of release of 14CO2 from [U-14C] asparate; (5) in isolated mitochondria, succinate and alpha-glycerol phosphate stimulate O2 consumption whereas substrates which generate NADH, such as malate, do not; and (6) there is little or no rotenone-sensitive NADH oxidase activity in isolated mitochondria.
mesh_terms: D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism; D002250:Carbon Radioisotopes; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D008168:Lung; D008928:Mitochondria / Q000378:metabolism*; D009154:Mutation; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D010101:Oxygen Consumption; D013385:Succinate Dehydrogenase / Q000378:metabolism
chemical_list: D002250:Carbon Radioisotopes; D002245:Carbon Dioxide; D013385:Succinate Dehydrogenase; D009247:NADH, NADPH Oxidoreductases