Partial Purification and Some Properties of a Hydroxycinnamoyl Glucosyltransferase from Tomato Fruits
Open Access
- 1 December 1980
- journal article
- Published by Walter de Gruyter GmbH in Zeitschrift für Naturforschung C
- Vol. 35 (11-12) , 967-972
- https://doi.org/10.1515/znc-1980-11-1217
Abstract
A glucosyltransferase was isolated from immature “cherry” tomatoes and was partially purified (200-fold) by ammonium sulphate precipitation and successive chromatography on Sephadex G-100 and DEAE-cellulose columns. The enzyme utilised the free hydroxycinnamic acids and UDP-glucose in the formation of their respective glucosides (pH 8.0) and glucose esters (pH 7.0); but did not accept the CoA thiolesters of HCAs in the presence of glucose-1-phosphate. The constant glucoside/glucose ester ratio observed during purification suggests that both reactions are catalysed by the same enzyme. The Km values for ρ-coumaric, caffeic, ferulic and sinapic acids were 0.8, 1.5, 1.4 and 2.5 μᴍ, respectively. With ferulic acid as substrate, the Km value for UDPG was 10 μᴍ. The enzyme required an -SH group for activity and the reaction was strongly inhibited by EDTA, divalent metal ions and UDP.Keywords
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