Futile cycles in Saccharomyces cerevisiae strains expressing the gluconeogenic enzymes during growth on glucose.

• DOI: 10.1073/pnas.90.4.1290
• Publication Date: 2006-05-31T12:39:41Z
• Authors: M A Navas; S Cerdán; J M Gancedo
• Keywords: Fructose 1,6-bisphosphatase; Gluconeogenesis; Fructolysis

The systems which control the levels of gluconeogenic enzymes in Saccharomyces cerevisiae have been bypassed to ascertain their physiological significance. coding regions genes FBP1 and PCK1, encode fructose-1,6-bisphosphatase phosphoenolpyruvate carboxykinase, put under promoter ADC1 (alcohol dehydrogenase I), a gene not repressed by glucose, introduced into yeast multicopy plasmids. transformed cells show high during growth on glucose. Generation time yield expressing either or carboxykinase are significantly different from those wild-type strain. For strain both increase generation is about 20% decrease around 30%. concentration ATP 1.5 mM growing strains. extent vivo cycling was measured 13C NMR cell-free extracts [6-13C]glucose. Cycling between fructose-6-phosphate fructose-1,6-bisphosphate < 2%, most likely due very strong inhibition fructose 2,6-bisphosphate. pyruvate low, but precise figure could be obtained poor equilibration label carbons 2 3 oxaloacetate.