Purification and characterization of UDPG : ginsenoside Rd glucosyltransferase from suspended cells of Panax notoginseng

作者 Yue, CJ; Zhong, JJ

期刊 PROCESS BIOCHEMISTRY , DEC 2005,12:40

DOI 10.1016/j.procbio.2005.05.001

摘要 Heterogeneity of ginsenosides is an interesting and important issue because those structure-similar secondary metabolites have different or even totally opposite pharmacological activities. In this work, a new enzyme UDP-glucose:ginsenoside Rd glucosyltransferase (UGRdGT), which catalyzes the formation of ginsenoside Rb-1 from ginsenoside Rd was purified approximately 145-fold from suspended cells of Panax notoginseng with an overall yield of 0.2%. Purification to apparent homogeneity, as judged by SDS-PAGE, was successfully achieved by using sequential ammonium sulphate precipitation, anion-exchange chromatography and native PAGE. The enzyme had a molecular mass of 36 kDa, and its activity was optimal at pH 8.5 and 35 degrees C. The enzyme activity was enhanced by Mn2+, Ca2+ and Mg2+, but strongly inhibited by Zn2+, Hg2+, Co2+, Fe2+ and Cu2+. The apparent K-m value for UDP-glucose and ginsenoside Rd was 0.32 and 0. 14 mM, respectively. The biotransformation yield from ginsenoside Rd to Rb-1 by UGRdGT in 50 mM Tris-HCl buffer at pH 8.5 and 35 degrees C was over 80%. This work provides a basis for further molecular study on the ginsenoside Rb-1 biosynthesis by P notoginseng cells and it is also useful for potential application to in vitro biotransformation from ginsenoside Rd to Rb-1. (c) 2005 Elsevier Ltd. All rights reserved.