Nomilin Acetyl-Lyase, a Bacterial Enzyme for Nomilin Debittering of Citrus Juices |
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Authors: | ZAREB HERMAN SHIN HASEGAWA PETER OU |
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Affiliation: | Authors Herman, Hasegawa and Ou are affiliated with the Fruit &Vegetable Chemistry Laboratory, USDA-ARS, 263 S. Chester Ave., Pasadena, CA 91106. |
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Abstract: | Nomilin acetyl-lyase, an enzyme responsible for the conversion of bitter nomilin to nonbitter obacunone was purified from cell-free extracts of Corynebacterium fuscians by (NH4)2SO4 precipitation, followed by HPLC gel filtration and ion exchange chromatography. The electrophoretically pure preparation represented a 1050-fold increase in specific activity with a recovery of 38%. The enzyme, (MW 90,000) required sulfhydryl groups for its catalysis, had a pH optimum of 8.5, a Km of 38.1 PM, and a Vmax of 4.83 μmoles/min. Obacunone A-ring lactone hydrolase, which catalyzes the conversion of obacunone to obacunoate, was also purified from the extract by HPLC gel filtration. |
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