Chemostat studies of microsomal enzyme induction inSaccharomyces cerevisiae
| Autor: | S. L. Kelly, K. R. Cliffe, I. Stansfield |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Hemeprotein
Blotting Western Bioengineering Saccharomyces cerevisiae Chemostat Applied Microbiology and Biotechnology Biochemistry Electron Transport Oxygen Consumption Cytochrome P-450 Enzyme System Microsomes Cytochrome b5 Genetics RNA Processing Post-Transcriptional Enzyme inducer Cytochrome Reductases Ethanol biology Cytochrome P450 Blotting Northern Molecular biology Cytochromes b5 Glucose Enzyme Induction biology.protein Microsome Limiting oxygen concentration Steady state (chemistry) DNA Probes Protein Processing Post-Translational Biotechnology |
| Zdroj: | Yeast. 7:147-156 |
| ISSN: | 1097-0061 0749-503X |
| DOI: | 10.1002/yea.320070208 |
| Popis: | Using cells grown in a chemostat at steady state, the levels of various components of the microsomal electron transport chain of Saccharomyces cerevisiae were examined. Cytochrome P450 haemoprotein levels measured in cells grown in medium with a dissolved oxygen concentration of 15% were induced between 10- and 20-fold over levels in cells grown in medium containing 70% dissolved oxygen concentation. An increase in the dilution rate of a culture growing in medium containing 15% dissolved oxygen resulted in an increase in the residual glucose concentration of the medium. This was paralleled by an increase in the microsomal levels of cytochrome P450. The rise could not be attributed either to increases in the concentration of ethanol in the chemostat or to an increase in the proportion of energy generated using fermentative pathways. However, this effect was not observed in cells grown in an oxygen concentration of 70%. Cytochrome b5 haemoprotein levels were also induced approximately three-fold by reducing the dissolved oxygen concentration from 70% to 15%. Changes in the medium glucose concentration from 0·03% to 1·6% (w/v) had no effect on the levels of this enzyme. Conversely, levels of cytochrome P450 NADPH reductase appeared lower in cells grown in 15% as opposed to 70% dissolved oxygen concentration. Northern slot blot analysis of total RNA extracted from chemostat-grown cells, probed with a C-14 sterol demethylase cytochrome P450 gene (cytochrome P450 LIA1), revealed a pattern of message induction which matched that of the cytochrome P450 haemoprotein, indicating that control of the levels of this enzyme was at least partially transcriptional. Qualitative examination of combined cytochrome P450 apoprotein and haemoprotein levels using Western blot analysis revealed a similar pattern of induction to that observed with Northern blotting. |
| Databáze: | OpenAIRE |
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