ISSN:
1432-072X
Keywords:
Isocitrate lyase
;
Induction
;
Catabolite repression
;
Catabolite inactivation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The synthesis of isocitrate lyase was induced by the presence of ethanol in the chemostat reaching a specific activity of 200 mU·mg-1 at this induced state. In glucoselimited, derepressed cells, 20 mU·mg-1 were detected and under repressed conditions isocitrate lyase activity was not detected. The sensitivity of gluconeogenic enzymes: cytoplasmic malate dehydrogenase; fructose 1,6-bisphosphatase and isocitrate lyase as well as the mitochondrial enzymes NADH dehydrogenase and succinate cytochrome c oxidase to glucose and galactose repression were studied in chemostat cultures. Our results show that galactose was less effective as a repressor than glucose. Malate dehydrogenase was completely inactivated by glucose, whereas galactose only produced a 78% decrease of specific activity. Fructose 1,6-bisphosphatase and isocitrate lyase were completely inactivated by both sugars but at different rate. Glucose produced an 85% decrease of specific activity of the mitochondrial enzymes whereas galactose only decrease an 67%.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00411238
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