Cell-free extracts from oak leaves were found to catalyze the esterification of 14C-labeled gallic acid and UDP-glucose. The product of the enzymatic reaction was identified as β-glucogallin by means of TLC and HPLC. The reaction proceded linearly with respect to time and protein concentration and had a pH-optimum at 7.0. Normal Michaelis-Menten kinetics were observed for the substrates gallic acid (KM = 1.1 mM) and UDP-glucose (2.3 mM). The new enzyme described here can be classified as UDP-glucose: gallate glucosyltransferase, and it is assumed that it catalyzes the first step in the biosynthesis of gallotannins. © 1982.
Gross, G. G. (1982). Synthesis of β-glucogallin from UDP-glucose and gallic acid by an enzyme preparation from oak leaves. FEBS Letters, 148(1), 67–70. https://doi.org/10.1016/0014-5793(82)81244-1