Purification and Properties of UDP-galactose 4-Epimerase from Bifidobacterium bifidum |
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Authors: | Lyang-ja Lee Akira Kimura Tatsurokuro Tochikura |
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Institution: | Department of Food Science and Technology, Kyoto University,Kyoto 606, Japan |
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Abstract: | UDP-galactose 4-epimerase (EC 5.1.3.2) was purified to a homogeneous state from Bifidobacterium bifidutn grown on a glucose medium. The molecular weight was estimated to be about 90,000. The purified enzyme was very stable and 60 % of its initial activity survived three months of storage at 4°C even at a low protein concentration (0.2 mg/ml). The optimum pH was 9.0, and the Km values for UDP-galactose and UDP-glucose were 5.4 × 10-4 M and 1.4×10 -3 M. UDP was a competitive inhibitor. The enzyme activity was stimulated by various sugar phosphates, but was slightly inhibited by fructose 1,6-diphosphate (FDP). A high concentration of galactose or glucose, which had no effect by itself, inhibited the activity in combination with UMP. The inhibition by FDP was also enhanced by combination with UMP. |
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Keywords: | Cistanche salsa (2E 6R)-8-hydroxy-2 6-dimethyl-2-octenoic acid osteoporosis ovariectomized mice |
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