Summary
Investigations into the properties of 6-PG dehydrogenase in cell free extracts of Escherichia coli revealed a pH optimum at pH 9.5 with a sharp decline on both sides of the optimum. The addition of 1.0×10-2 m MgCl2 produced maximal activity, whereas higher concentrations caused inhibition. The K m values were 2.5×10-4 m for 6-phosphogluconate and 2.5×10-5 m for NADP+ as substrate. The enzyme was extremely stable for at least 5 hours if stored at 4°C in Tris−NaCl−MgCl2 buffer at pH 7.5. 6-PG dehydrogenase activity was shown to be proportional to cell free extract concentration over the range 0–0.3 mg protein. An assay method based on the new optimal conditions has been established and has been shown to be 33% more sensitive than a number of commonly used methods.
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Chattaway, F. W., C. C. Thompson, and A. J. R. Barlow: Carbohydrate metabolism in Microsporum canis. J. gen. Microbiol. 22, 649 (1960).
DeMoss, R. D.: Glucose-6-phosphate and 6-phosphogluconic dehydrogenase from Leuconostoc mesenteroides. In: Methods in Enzymology, ed. by S. P. Colowick and N. O. Kaplan, p. 328. New York: Academic Press 1955.
Dickens, F., and G. E. Glock: Direct oxidation of glucose-6-phosphate, 6-phosphogluconate and pentose-5-phosphate by enzymes of animal origin. Biochem. J. 50, 81 (1952).
Doelle, H. W.: Bacterial metabolism. New York: Academic Press (in print, 1968).
Glock, G. E., and P. McLean: Further studies on the properties and assay of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase of rat liver. Biochem. J. 55, 400 (1953).
Horecker, B. L., and P. Z. Smyrniotis: Phosphogluconic acid dehydrogenase from yeast. J. biol. Chem. 193, 371 (1951).
Jagannathan, V., P. N. Rangachari, and M. Damodaran: Carbohydrate metabolism in citric acid fermentation. 5. Purification and properties of Zwischenferment from Aspergillus niger. Biochem. J. 64, 477 (1956).
Lineweaver, H., and D. Burk: The determination of enzyme dissociation constants. J. Amer. chem. Soc. 56, 658 (1934).
Machida, Y., S. Mitzushima, and K. Kitahara: Quantitative studies on glycolytic enzymes in Lactobacillus plantarum II. VI. Intracellular activity of glucose-6-phosphate dehydrogenase during lactic acid fermentation. J. gen. appl. Microbiol. (Japan), 9, 433 (1963).
Pontremoli, S., A. DeFlora, E. Grazi, G. Mangiarotti, A. Bonsigmere, and B. L. Horecker: Crystalline D-gluconate-6-phosphate dehydrogenase. J. biol. Chem. 236, 2975 (1961).
—: Crystalline D-gluconate-6-phosphate dehydrogenase from Candida utilis. In: Biochem. Preparations, ed. by A. C. Maehly, 11, 45. New York: John Wiley and Sons 1966.
Scott, D. B. M., and S. E. Cohen: The oxidative pathway of carbohydrate metabolism. I. The isolation and properties of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. Biochem. J. 55, 23 (1953).
Sly, L. I. and H. W. Doelle: Glucose-6-phosphate dehydrogenase in cell free extracts of Zymomonas mobilis. Arch. Mikrobiol. 63, 197–213 (1968).
Srivastava, L. M., and G. Hubscher: Glucose metabolism in the mucosa of the small intestine. Enzymes of the pentose phosphate pathway. Biochem. J. 101, 48 (1966).
Wright, D. N., and W. H. Lockhart: Environmental control of cell composition in Escherichia coli. J. Bact. 89, 1026 (1965).
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Sly, L.I., Doelle, H.W. 6-Phosphogluconate dehydrogenase in cell free extracts of Escherichia coli K-12 . Archiv. Mikrobiol. 63, 214–223 (1968). https://doi.org/10.1007/BF00412837
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DOI: https://doi.org/10.1007/BF00412837