Glucose-6-phosphate Dehydrogenase and 6-Phosphogluconate Dehydrogenase of Candida tropicalis Partial Purification and Some Properties |
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Authors: | Atsuo Tanaka Yoshinori Takenaka Masana Hirai Saburo Fukui |
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Affiliation: | Laboratory of Industrial Biochemistry, Department of Industrial Chemistry, Faculty of Engineering, Kyoto University, Kyoto |
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Abstract: | Glucose-6-phosphate (G6P) dehydrogenase and 6-phosphogluconate (6PG) dehydrogenase were partially purified about 53-fold and 47-fold, respectively, from the cell-free extract of glucose-grown Candida tropicalis by means of ammonium sulfate fractionation and DEAE-cellulose column chromatography. AMP acted as the competitive inhibitor against G6P and NADP in the G6P dehydrogenase reaction. This inhibition was remarkable at low concentrations of NADP, increasing the sigmoidicity of the NADP-saturation curve. On the other hand, 6PG dehydrogenase was not affected by AMP. Fructose-1,6-bisphosphate (FDP) and phosphoenolpyruvate (PEP) inhibited slightly G6P dehydrogenase. 6PG dehydrogenase was also weakly inhibited by FDP. Apparent Km values of G6P dehydrogenase were calculated as 1.8 × 10?4 m for G6P and 3.1 × 10?5 m for NADP. Those of 6PG dehydrogenase were 9.4 × 10?5 m for 6PG and 2.8 × 10?5 m for NADP. |
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Keywords: | Saccharomyces cerevisiae epigenetic gene regulation ethanol tolerance stress response histone deacetylase |
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