Studies on d-Glucose-isomerizing Activity of d-Xylose-grown Cells from Bacillus coagulans,Strain HN-68 |
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Authors: | Gen-ichi Danno Sadahiko Yoshimura Masato Natake |
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Institution: | Laboratory of Food Chemistry and Applied Microbiology, Hyogo University of Agriculture, Sasayama, Hyogo Prefecture |
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Abstract: | d-Glucose-isomerizing enzyme has been extracted in high yield from d-xylose-grown cells of Bacillus coagulans, strain HN-68, by treating with lysozyme, and purified approximately 60-fold by manganese sulfate treatment, fractionation with ammonium sulfate and chromatography on DEAE-Sephadex column. The purified d-glucose-isomerizing enzyme was homogeneous in polyacrylamide gel electrophoresis and ultracentrifugation and was free from d-glucose-6-phosphate isomerase. Optimum pH and temperature for activity were found to be pH 7.0 and 75°C, respectively. The enzyme required specifically Co++ with suitable concentration for maximal activity being 10?3 m. In the presence of Co++, enzyme activity was inhibited strongly by Cu++, Zn++, Ni++, Mn++ or Ca++. At reaction equilibrium, the ratio of d-fructose to d-glucose was approximately 1.0. The enzyme catalyzed the isomerization of d-glucose, d-xylose and d-ribose. Apparent Michaelis constants for d-glucose and d-xylose were 9×10?2 m and 7.7×10?2 m, respectively. |
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