title: New dioscin-glycosidase hydrolyzing multi-glycosides of dioscin from Absidia strain.
abstract: A novel dioscin-glycosidase that specifically hydrolyzes multi-glycosides such as 3-O-alpha-L-(1 --> 4)-rhamnoside, 3-O-alpha-L-(1 --> 2)-rhamnoside, 3-O-alpha-L-(1 --> 4)-arabinoside and beta-D-glucoside on diosgenin was isolated from Absidia sp.d38 strain; and it was purified and characterized. The molecular weight of the new dioscin-glycosidase is about 55 kDa in SDS-PAGE. The the dioscin-glycosidase gradually hydrolyzes either 3-O-alpha-L-(1 --> 4)-Rha or 3-O-alpha-L-(1 --> 2)-Rha of dioscin to 3-O-alpha-L-Rha-beta-D-Glc-diosgenin; further rapidly hydrolyzes the other alpha-L-Rha of 3-O-alpha-L-Rha-beta-D-Glc-diosgenin to main intermediate products 3-O-beta-D-glc-diosgenin; and subsequently hydrolyzes intermediate products to final product of aglycone; the new enzyme also gradually hydrolyzes 3-O-alpha-L-(1 --> 4)-arabinoside, 3-O-alpha-L-(1 --> 2)-rhamnoside and beta-D-glucoside of [3-O-alpha-L-(1 --> 4)-Ara, 3-O-alpha-L-(1 --> 2)-Rha]-beta-D-Glc-diosgenin into final product diosgenin, exhibiting significant differences from previously reported glycosidases. The optimal temperature of the new dioscin-glycosidase is 40 degrees C and the optimal pH is 5.0. The activity of the new dioscin-glycosidase was not affected by the Na+, K+ and Mg2+ ions; it was significantly inhibited by the Cu2+ and Hg2+ ions; and it was slightly affected by the Ca2+ ions.
authors.affiliation: College of Science, Yanbian University, Yanji City 133002, China.
authors.forename: Yaoyao
authors.initials: Y
authors.lastname: Fu
authors.forename: Hongshan
authors.initials: H
authors.lastname: Yu
authors.forename: Si Hui
authors.initials: SH
authors.lastname: Tang
authors.forename: Xiangchun
authors.initials: X
authors.lastname: Hu
authors.forename: Yuanhao
authors.initials: Y
authors.lastname: Wang
authors.forename: Bing
authors.initials: B
authors.lastname: Liu
authors.forename: Chenxu
authors.initials: C
authors.lastname: Yu
authors.forename: Fengxie
authors.initials: F
authors.lastname: Jin
mesh_terms: D020095:Absidia / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism; D004144:Diosgenin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D006027:Glycosides / Q000737:chemistry / Q000378:metabolism*; D006868:Hydrolysis; D007700:Kinetics
chemical_list: D005656:Fungal Proteins; D006027:Glycosides; C019357:dioscin; D006026:Glycoside Hydrolases; D004144:Diosgenin