The properties of a partially purified uridine-5'-diphosphoglucose (UDP-glu
cose)- crocetin 8,8'-glucosyltransferase (EC 2.4.1.) involved in crocin syn
thesis are described. The enzyme participates in the biosynthesis of crocin
by forming ester bonds between the carboxyl groups of crocetin and the glu
cose moiety of UDP-glucose. The enzyme has been purified 125-fold trough a
multi-step process of acetone fractionation, anion-exchange, and gel filtra
tion chromatography. The native molecular weight is in the range of 47 kDa,
as estimated by analytical gel filtration. The most purified preparation s
howed isoforms between pH 4.4 and 4.8 when resolved by IEF. The enzyme had
maximal activity at 40 degrees C, apparent K-m values for UDP-glucose and c
rocetin were 0.72 and 0.17 mM, respectively, and V-max, 30 pkatal/mg. (C) 2
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