Effects of Adding Intermediate Material in Tricarboxylic Acid Cycle on the Activity of Key Enzymes of Saccharomyces cerevisiae

Abstract:

The enzyme activity of some key metabolic enzymes (pyruvate kinase, glucose-6-phosphate dehydrogenase, isocitrate dehydrogenase, malate dehydrogenase and ethanol dehydrogenase) in Saccharomyces cerevisiae with YEPD medium were compared with malic aicd, citric acid and succinic acid mixed medium. The result showed that after adding malic acid, enzymatic activity of pyruvate kinase, isocitrate dehydrogenase, malate dehydrogenase and ethanol dehydrogenase respectively declined 34.82%, 57.23%, 39.15% and 12.10%; after adding citric acid, enzymatic activity of pyruvate kinase, isocitrate dehydrogenase and malate dehydrogenase respectively declined 50.17%, 42.20% and 48.40%; after adding succinic acid, enzymatic activity of pyruvate kinase, glucose-6-phosphate dehydrogenase, isocitrate dehydrogenase, malate dehydrogenase and ethanol dehydrogenase respectively declined 34.16%, 34.16%, 50.87%, 50.87% and 12.37%. Pyruvate kinase, isocitrate dehydrogenase and malate dehydrogenase had bad tolerance to three kinds of organic acids, tolerance of glucose-6-phosphate dehydrogenase and ethanol dehydrogenase to three kinds of organic acids had selectivity.

Key words:Saccharomyces cerevisiae, TCA cycle, Enzymatic activity, Organic acids