Purification and Properties of an Asymmetric Reduction Enzyme of 2-Methyl-3-oxobutyrate in Baker’s Yeast |
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Authors: | Akiya Furuichi Hiroyuki Akita Hiroko Matsukura Takeshi Oishi Koki Horikoshi |
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Institution: | The Institute of Physical and Chemical Research, Wako-shi, Saitama, 351, Japan |
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Abstract: | The benzyl 2-methyl-3-hydroxybutyrate dehydrogenase was purified from the cells of baker’s yeast by streptomycin treatment, Sephadex G-50 gel filtration, SP-Sephadex C-50 chromatography, and Toyopearl HW-60F gel filtration. The purified enzyme preparation was homogeneous and the molecular weight was about 31,000 to 32,000. The enzyme was NADPH-dependent and its maximum activity was at pH 7.0 and 45°C. It was stable between pH 6 and 9. The Km values at pH 7.0 were 0.42 mM for benzyl 2-methyl-3-oxobutyrate (1) and 4.2 mM for α-methyl β-hydroxy ester syn-(2) and anti-(3)]. This enzyme reduced only benzyl 2-methyl-3-oxobutyrate (1) but had no effect on other synthetic substrates.The reduced products syn-(2) and anti(3)] produced by the purified enzyme were identified by 400 MHz NMR. |
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