ISSN:
1573-6881
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Physics
Notes:
Abstract Cytochrome c oxidase extracted from a yeast auxotroph grown on different fatty acid supplements, and assayed at various temperatures (0→37°), gives transition points (Tt) when the data are expressed in an Arrhenius plot: Tt for linoleic, oleic and elaidic acids were 7.7°, 10.2° and 21.8° respectively. Lipid anlaysis of isolated mitochondria established that there is a change in lipid profile when yeast is first grown aerobically on linoleic acid and then transferred to elaidic acid under anaerobic consitions. These two observations bave been used as a basis for the investigation of the assembly of cytochrome c oxidase when cells are oxygen induced for mitochondriogenesisvia a linoleic, N2 elaidic, O2 transfer experiment. A three-stage assembly process is proposed consisting of (i) 0.0→0.25 h, auto-assembly of oxidase from preformed, chloramphenicol-sensitive precursors and newly synthesized cycloheximide-sensitive precursors, (ii) 0.25 h→0.5h, a continuation of (i) plusde novo synthesis of new precursors of both kinds and (iii) 0.5 h onwards; normal, synchronisedde novo synthesis. This model predicts one population of oxidase molecules at 0.0 h (linoleic Tt) and two populations of oxidase at 0.5 h (end of stage (ii)); one from the anaerobic precursors (linoleic Tt) and one for thede nove, aerobic oxidase (elaidic Tt): these predictions are confirmed by Arrhenius profiles constructed from samples taken at 0.0, 0.5, 1.0 and 3.0 h after oxygen challenge.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01648981
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