Biosynthesis Of Gallotannins. ß-Glucogallin-Dependent Galloylation Of 1,6-Digailoylglucose To 1,2,6-Trigalloylglucose
Open Access
- 1 June 1991
- journal article
- Published by Walter de Gruyter GmbH in Zeitschrift für Naturforschung C
- Vol. 46 (5-6) , 389-394
- https://doi.org/10.1515/znc-1991-5-609
Abstract
An enzyme from leaves of sumach (Rhus typhina) was partially purified that catalyzes the β-glucogallin (l-O-galloylglucose)-dependent galloylation of 1,6-digalloylglucose, thus forming 1,2,6-trigalloylglucose and free glucose. This acyltransferase had a molecular weight of ca. 750,000 and a pH optimum at 5.0-5 .5. Besides β-glucogallin (Km = 3.9 mM ) , also related 1-O-phenylcarboxylglucoses acted as acyl donors. On the other hand, the acceptor substrate, 1,6-digalloylglucose (Km = 0.9 mM ) , could only be replaced by 1,6-diprotocatechuoylglucose (relative activity 46%); however, also tri-, tetra-, and pentagalloylglucoses were galloylated. A pronounced stimulation of the enzymatic reaction was observed upon addition of penta- or hexagalloylglucose into the assay mixtures. The systematic name “ β-glucogallin: 1,6-di-O-galloylglucose 2-O-galloyltransferase” (EC 2.3.1. - ) is proposed for the enzymeKeywords
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