UDP-glucose Pyrophosphorylase from Tubers of Jerusalem Artichoke (Helianthus tuberosus L.) |
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Authors: | Kiyotaka Otozai Hajime Taniguchi Michinori Nakamura |
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Affiliation: | Department of Agricultural Chemistry, The University of Tokyo, Bunkyo-ku, Tokyo |
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Abstract: | UDP-glucose pyrophosphorylase of Jerusalem artichoke tubers was purified 90-fold over the crude extract. The purified enzyme preparation absolutely required magnesium ions for activity. Cobalt ions were 60% as effective as magnesium ions; other divalent cations including manganese showed little or no effect. This enzyme had a pH optimum of 8.5 and a temperature optimum of 40°C. ATP and UDP inhibited the activity of this enzyme in both forward and backward directions. Km values for UDP-glucose, inorganic pyrophosphate, glucose-1-phosphate and UTP were determined to be 4.45 × 10?4 M, 2.33 × 10?4 M, 9.38 × 10?4 M and 2.98 × 10?4 M, respectively. These results are discussed in comparison with those of UDP-glucose pyrophosphorylases isolated from other plants. |
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Keywords: | cellulase-free xylanases Plackett-Burman design central composite design (CCD) Streptomyces thermovulgaris rice straw |
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