The function of redox shuttles during aerobic glycolysis in two strains of Ehrlich ascites tumor cells |
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Authors: | Francisca Sánchez-Jiménez Pedro Martínez Ignacio Núñez de Castro Jesús S Olavarría |
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Institution: | Departamento de Bioquímica, Facultad de Ciencias, Universidad de Málaga, 29004 Málaga, Spain |
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Abstract: | The function of glycerophosphate and malate-aspartate shuttles during glucose metabolism in two strains of Ehrlich ascites tumor cells was evaluated by several experimental approaches. The activities of the enzymes involved in these shuttle systems were assayed in the cytosolic and mitochondrial compartments after cell fractionation by the digitonin method. The glycerophosphate shuttle can be ruled out because of the lack of relevant enzymatic activities, and the failure of glucose to increase rotenone-inhibited respiration. Analysis of glycolytic flux in the presence of aminooxyacetate indicates that the activity of malate-aspartate shuttle may be very low. Balance studies of glucose uptake and lactate production suggest the existence of other pathways for the reoxidation of cytosolic NADH, which are acetyl-CoA dependent. Estimation of citrate synthase and ATP citrate lyase, in addition to the observed high activity of malate dehydrogenase, suggests a malate-citrate shuttle. |
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Keywords: | cycle du phospho-3-glycérate cycle du malate-aspartate respiration glycolyse cellules tumorales d'ascites shuttle ascites cells respiration glucose metabolism |
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