Mutations in phosphofructokinases alter the control characteristics of glycolysis in vivo in Saccharomyces cerevisiae.

Lloyd, D ORCID: https://orcid.org/0000-0002-5656-0571, James, C J and Maitra, P K 1992. Mutations in phosphofructokinases alter the control characteristics of glycolysis in vivo in Saccharomyces cerevisiae. Yeast 8 (4) , 291--301. 10.1002/yea.320080406

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Abstract

Ethanol and CO2 production from glucose by non-proliferating suspensions of aerobically-grown, glucose-derepressed wild-type Saccharomyces cerevisiae is inhibited by O2; monitoring by mass spectrometry provides a direct method for measurement of the Pasteur effect. Under aerobic conditions, that part of the CO2 evolved equivalent to the O2 consumed, is produced by respiration: subtraction of this respiratory CO2 from the total gives CO2 produced by aerobic glycolysis. Pasteur quotients (anaerobic CO2/aerobic glycolytic CO2) were within the range 1.2 to 3.0. The Pasteur effect was not observed in the presence of carbonyl cyanide m-chlorophenylhydrazone, an uncoupler of mitochondrial energy metabolism, or in a rho degree cytoplasmic petite mutant. A 'non-allosteric' mutant with an altered regulatory subunit of phosphofructokinase showed no Pasteur effect. Strains bearing a nonsense mutation pfk1 in the catalytic subunit of soluble phosphofructokinase (PFKI) also showed no Pasteur effect; the residual fermentative activity of this strain was dependent on PFKII, the particulate phosphofructokinase. A double mutant lacking both PFKI and glucose-6-phosphate dehydrogenase showed similar characteristics to those of the single pfk1 mutant; this indicates that the hexose monophosphate shunt is not acting to bypass the phosphofructokinase block. A 'hyper-allosteric' mutant altered in the regulatory subunit encoded by the gene PFK2 showed characteristics of glucose fermentation and ethanol oxidation very similar to those of wild-type organisms. These results indicate that either of the two phosphofructokinases can carry out glycolysis.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Biosciences
Publisher:	Wiley
ISSN:	0749-503X
Date of Acceptance:	10 December 1991
Last Modified:	26 Oct 2022 08:34
URI:	https://orca.cardiff.ac.uk/id/eprint/127790

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