Induction of Cytochrome <i>P</i>-450 in Yeast by Phenobarbital

Wiseman, Alan; Lim, T.-K.

doi:10.1042/bst0030974

Cited by 23 publications

(2 citation statements)

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“…The tested chemicals certainly affected growth and metabolism of the yeasts, which may lead to conditions favoring cytochrome P-450 biosynthesis as, for example, a shift to more pronounced fermentative metabolism. The same comment is valid for the results of Wiseman and Lim (102), who reported the induction of a cytochrome P-450 when the cells grew in the presence of phenobarbital.…”

Section: Physiol In Presssupporting

confidence: 75%

Cytochromes P-450 of yeasts.

Käppeli¹

1986

Microbiological Reviews

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Section: Physiol In Presssupporting

confidence: 75%

Cytochromes P-450 of yeasts.

Käppeli¹

1986

Microbiological Reviews

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“…Wiseman et al (1975a) showed that the concentration of cytochrome P-450 was independent of glucose concentrations above 1% in yeast grown aerobically. Wiseman & Lim (1975) observed no production of cytochrome P-450 on 0.5% glucose.…”

Section: Printed In Great Britainmentioning

confidence: 82%

Effect of carbon source on the accumulation of cytochrome P-450 in the yeast Saccharomyces cerevisiae

Kärenlampi¹,

Marín²,

Hänninen³

1981

Biochemical Journal

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The appearance of cytochrome P-450 in the yeast Saccharomyces cerevisiae depended on the substrate supporting growth. Cytochrome P-450 was apparent in yeast cells grown on a strongly fermentable sugar such as D-glucose, D-fructose or sucrose. When yeast was grown on D-galactose, D-mannose or maltose, where fermentation and respiration occurred concomitantly, cytochrome P-450 was also formed. The cytochrome P-450 concentration was maximal at the beginning of the stationary phase of the culture. Thereafter the concentration decreased, reaching zero at a late-stationary phase. When the yeast was grown on a medium that contained lactose or pentoses (L-arabinose, L-rhamnose, D-ribose and D-xylose), cytochrome P-450 did not occur. When a non-fermentable energy source (glycerol, lactate or ethanol) was used, no cytochrome P-450 was detectable. Transfer of cells from D-glucose medium to ethanol medium caused a slow disappearance of cytochrome P-450, although the amount of the haemoprotein still continued to increase in the control cultures. Cytochrome P-450 appeared thus to accumulate in conditions where the rate of growth was fast and fermentation occurred. Occurrence of this haemoprotein is not necessarily linked, however, with the repression of mitochondrial haemoprotein synthesis.

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Food group symposium short paper reading meeting

et al. 1978

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Single-cell proteins have significant potential for use as food additives or as major components of processed foods. However, a number of problems associated with single-cell protein have to be solved to render it a safe and cheap source of protein for human use. Proteins from yeast cells should be low in cell wall fragments to maximise nutritional value; nucleic acid (essentially RNA) content should be minimised to reduce its intake to less than 2 g per day: the protein should have acceptable colour, flavour and texture. The above requirements can be met if suitable methods for the extraction and isolation of the protein from cellular material can be achieved economically.Our initial studies with single-cell proteins have centred on baker's yeast containing more than 10 % nucleic acid.The first requirement of the investigation, 100 % disintegration of the yeast cell walls, has been achieved by mechanical agitation in aqueous suspension. Ultrasonication and enzymic degradation both succeeded only partially. The disintegrator was of 500 ml capacity, handling yeast suspension in a mild steel vessel with a high-powered stirrer agitation in the presence of Ballotini beads. Disintegration was monitored by counting intact cells under the microscope after staining with methylene blue. A supplementary staining technique for cell walls provided confirmatory indication of the site of breakage. Protein was extracted from the disintegrated biomass by adjusting the pH to 11.8 and centrifuging the resulting slurry. The supernatant was either (a) incubated with salt to activate endogenous enzymes capable of degrading nucleic acids, or (b) brought to pH 4.5 to precipitate protein isolate at its iso-electric point. In the former case, after incubation, a second isolate, low in nucleic acids was obtained by method (b). Both isolates as well as cell-wall material were stored after freezedrying.Various parameters have been modified in these studies in order to optimise protein yield and quality. The protein content rose from 55 % in the freeze-dried intact yeast cells to above 90% in the isolates. The amino acid profiles of the protein preparations were satisfactory: nucleic acid levels were reduced to about one-quarter of their original value.

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Induction of Cytochrome P-450 in Yeast by Phenobarbital

Cited by 23 publications

References 0 publications

Cytochromes P-450 of yeasts.

Cytochromes P-450 of yeasts.

Effect of carbon source on the accumulation of cytochrome P-450 in the yeast Saccharomyces cerevisiae

Food group symposium short paper reading meeting

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