The importance of ATP as a regulator of glycolytic flux in Saccharomyces cerevisiae.
The control of glycolytic flux in the yeast Saccharomyces cerevisiae was studied by using permeabilized cells. Cells were harvested from chemostat cultures and, after removal of the cell wall, nystatin was used to permeabilize the spheroplasts. By this method it is possible to study the performance and regulation of a complete and functional metabolic pathway and not only a single enzymatic step. The results showed that ATP has a strong negative effect on glycolytic activity affecting several of the glycolytic enzymes. However, the main targets for ATP inhibition was phosphofructokinase and pyruvate kinase. Phospofructokinase was inhibited by ATP concentrations starting at about 1-2 mM, while pyruvate kinase required ATP levels above 2.5 mM before any inhibition was visible. These ATP concentrations were in the same range as measured for nitrogen- and glucose-limited cells cultivated in chemostat cultures. Other potential candidates as enzymes susceptible to ATP inhibition included hexokinase and enolase. The ATP:ADP ratio, as well as trehalose-6-phosphate levels, did not seem to influence the glycolytic activity.
Larsson
C
C
Department of Molecular Biotechnology, Chalmers University of Technology, Box 462, S-405 30 Göteborg, Sweden. Christer.Larsson@gmm.gu.se
Påhlman
I L
IL
Gustafsson
L
L
D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism* / Q000494:pharmacology; D000693:Anaerobiosis; D002463:Cell Membrane Permeability; D003470:Culture Media; D005947:Glucose / Q000378:metabolism; D006019:Glycolysis; D009243:NAD / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000378:metabolism*; D013379:Substrate Specificity; D013403:Sugar Phosphates / Q000378:metabolism; D014199:Trehalose / Q000031:analogs & derivatives / Q000378:metabolism
D003470:Culture Media; D013403:Sugar Phosphates; D009243:NAD; C082722:trehalose-6-phosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D014199:Trehalose; D005947:Glucose; D009584:Nitrogen