Bulge Formation in Escherichia coli Induced by l-Arabinose under Hypertonic Conditions with Sodium Chloride |
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| Authors: | Toshio Tanaka Gaysorn Dhavises Makoto Taniguchi Susumu Oi |
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| Affiliation: | 1. Department of Biology, Faculty of Science, Osaka City University, Sumiyoshi-ku, Osaka 558, Japan;2. Department of Microbiology, Faculty of Science, Kasetsart University, Kamphaengsaen, Nakornpathom 73140, Thailand |
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| Abstract: | A pseudotropine-forming tropinone reductase was extracted from root cultures of Hyoscyamus niger that produce the tropane alkaloids hyoscyamine and scopolamine. The enzyme stereospecifically reduces tropinone to pseudotropine, oxidizing NADPH. It has an approximate molecular weight of 84,000 and a pH optimum between 5.8 and 6.25. The Km value for tropinone is 35.1 μmol/l and for NADPH 21.1 μmol/l. Substrate specificity was tested for NADPH and several tropinone analogues. |
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