The potential applications of glycosyltransferases in glycoconjugate synthesis have attracted considerable interest from the biotechnology community in recent years. In this work, we present a novel glucosyltransferase from Catharanthus roseus cell cultures. The enzyme was purified to one spot in SDS-polyacrylamide gel electrophoresis, and its molecular weight was about 51kDa. The optimum temperature was 35°C, and the optimum pH was 7.6. Sodium ion has weak effect on enzyme activity, whereas divalent ions inhibit enzyme activity strongly. The K m values were 0.112, 0.077, 0.064 and 1.0mM for scopoletin, 5,7-dihydroxyflavone, 5,7-dihydroxyflavanone and UDPG, respectively. Substrate screening with the purified enzyme was performed against a range of phenolic compounds using UDPG as sugar donor. The enzyme showed activity towards a number of coumarins including umbelliferone, scopoletin, isoscopoletin and esculetin, and flavonoids including a flavone, a flavanone and chalcones. No activity was detected with compounds characterized by a single aromatic ring, i.e. simple and acidic phenols. The substrate specificity and the regioselectivity suggest enzyme structural features that are different from those of other glucosyltransferases.