title: Purification and partial characterization of beta-glucosidase from fresh leaves of tea plants (Camellia sinensis (L.) O. Kuntze).
abstract: beta-Glucosidases are important in the formation of floral tea aroma and the development of resistance to pathogens and herbivores in tea plants. A novel beta-glucosidase was purified 117-fold to homogeneity, with a yield of 1.26%, from tea leaves by chilled acetone and ammonium sulfate precipitation, ion exchange chromatography (CM-Sephadex C-50) and fast protein liquid chromatography (FPLC; Superdex 75, Resource S). The enzyme was a monomeric protein with specific activity of 2.57 U/mg. The molecular mass of the enzyme was estimated to be about 41 kDa and 34 kDa by SDS-PAGE and FPLC gel filtration on Superdex 200, respectively. The enzyme showed optimum activity at 50 deg;C and was stable at temperatures lower than 40 degrees C. It was active between pH 4.0 and pH 7.0, with an optimum activity at pH 5.5, and was fairly stable from pH 4.5 to pH 8.0. The enzyme showed maximum activity towards pNPG, low activity towards pNP-Galacto, and no activity towards pNP-Xylo.
authors.affiliation: Key Laboratory of Tea Biochemistry and Biotechnology, Ministry of Education, Anhui Agricultural University, Hefei 230036, China.
authors.forename: Ye-Yun
authors.initials: YY
authors.lastname: Li
authors.forename: Chang-Jun
authors.initials: CJ
authors.lastname: Jiang
authors.forename: Xiao-Chun
authors.initials: XC
authors.lastname: Wan
authors.forename: Zheng-Zhu
authors.initials: ZZ
authors.lastname: Zhang
authors.forename: Da-Xiang
authors.initials: DX
authors.lastname: Li
mesh_terms: D028241:Camellia sinensis / Q000201:enzymology*; D002852:Chromatography, Ion Exchange; D002853:Chromatography, Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D018515:Plant Leaves / Q000201:enzymology*; D013379:Substrate Specificity; D013696:Temperature; D001617:beta-Glucosidase / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D001617:beta-Glucosidase