title: Spectroscopic studies of flavoproteins and non-haem iron proteins of submitochondrial particles of Torulopsis utilis modified by iron- and sulphate-limited growth in continuous culture.
abstract: 1. A spectroscopic resolution has been made of the components contributing to the ;iron-flavoprotein' trough extending from 450 to 520nm in the reduced-minus-oxidized difference spectrum of submitochondrial particles of Torulopsis utilis. 2. Seven components were identified other than cytochrome b, ubiquinone and succinate dehydrogenase. On the basis of the effects of iron- and sulphate-limited growth of cells on their subsequently derived electron-transport particles, and also by consideration of analytical measurements of the concentration of FMN, FAD, non-haem iron and acid-labile sulphide in the electron-transport particles in relation to the magnitude of the spectroscopic changes, it was possible to identify five of these components as follows: species 1a, the flavin of NADH dehydrogenase ferroflavoprotein; species 1b, the iron-sulphur component of NADH dehydrogenase ferroflavoprotein; species 1', the flavin of an NADPH dehydrogenase; species 2, an iron-sulphur or ferroflavoprotein component; species 3, the flavin of l-3-glycerophosphate dehydrogenase. Two additional components were a fluorescent flavoprotein, probably lipoamide dehydrogenase, and a b-type cytochrome reducible by NADH or NADPH but not reoxidizable by the respiratory chain. 3. Species 1b and 2 were undetectable in electron-transport particles from iron- or sulphate-limited cells, but could be recovered in vivo under non-growing conditions. 4. The recovery in vivo of species 2 but not species 1b was inhibited by cycloheximide. 5. The recovery of species 1b correlates with the recovery of site 1 conservation. 6. The recovery of species 1b with species 2 correlates with the recovery of piericidin A sensitivity. 7. Evidence is presented for an NADPH dehydrogenase distinct from NADH dehydrogenase. The oxidation of NADH and NADPH by the respiratory chain is sensitive to piericidin A, and an iron-sulphur protein common to both pathways (species 2) is suggested as the piericidin A-sensitive component. 8. The approximate E'(0) (pH7.0) values of species 1 (a and b, low potential) and species 2 (high potential) indicate that site 1 energy conservation occurs between the levels of species 1 (a and b) and species 2.
mesh_terms: D003513:Cycloheximide / Q000494:pharmacology; D003580:Cytochromes / Q000378:metabolism; D004579:Electron Transport; D005486:Flavin Mononucleotide / Q000032:analysis; D005182:Flavin-Adenine Dinucleotide / Q000032:analysis; D005420:Flavoproteins / Q000032:analysis; D005993:Glycerolphosphate Dehydrogenase / Q000378:metabolism; D006418:Heme; D007501:Iron / Q000378:metabolism*; D008928:Mitochondria / Q000032:analysis / Q000378:metabolism*; D003904:Mitosporic Fungi / Q000378:metabolism*; D009243:NAD; D009249:NADP; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism; D011506:Proteins / Q000032:analysis*; D013057:Spectrum Analysis; D013385:Succinate Dehydrogenase / Q000378:metabolism; D013431:Sulfates / Q000378:metabolism*; D013440:Sulfides / Q000032:analysis; D014451:Ubiquinone
chemical_list: D003580:Cytochromes; D005420:Flavoproteins; D011506:Proteins; D013431:Sulfates; D013440:Sulfides; D009243:NAD; D014451:Ubiquinone; D005182:Flavin-Adenine Dinucleotide; D006418:Heme; D009249:NADP; D005486:Flavin Mononucleotide; D003513:Cycloheximide; D007501:Iron; D010088:Oxidoreductases; D005993:Glycerolphosphate Dehydrogenase; D013385:Succinate Dehydrogenase