Summary
Glucose-6-phosphate dehydrogenase activity in cell free extracts o Zymomonas mobilis showed marked differences when compared with the corresponding enzyme of Escherichia coli. It exhibited 3 times higher activity and the reaction rate over 10 min gave linearity only up to a cell free protein concentration of 0.15 mg protein. This different behaviour was not a function of environmental growth conditions of the culture nor of the nine different assay methods employed. A constant relationship existed between the specific G-6-P dehydrogenase protein and the total protein concentration in the cell free extract. The enzyme was stable for at least 5 h at 4°C in Tris-NaCl-MgCl2-buffer.
An investigation of the properties of G-6-P dehydrogenase from Z. mobilis revealed a pH optimum of 8.7 with a rapid decline towards the acidic and a small decrease towards the alkaline side. The K m values were 5×10-4 m for glucose-6-phosphate and 3.6×10-5 m NADP+. The addition of 1×10-2 m MgCl2 produced optimal activity but higher concentrations inhibited the enzyme reaction.
These results were discussed with those from other sources and found to be unique for Zymomonas mobilis.
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Sly, L.I., Doelle, H.W. Glucose-6-phosphate dehydrogenase in cell free extracts of Zymomonas mobilis . Archiv. Mikrobiol. 63, 197–213 (1968). https://doi.org/10.1007/BF00412836
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DOI: https://doi.org/10.1007/BF00412836