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Purification and characterization of flavone-specific β-glucuronidase from callus cultures of Scutellaria baicalensis Georgi
Satoshi Morimoto, Takahiro Harioka and Yukihiro Shoyama
Vol. 195, No. 4 (1995), pp. 535-540
Published by: Springer
Stable URL: http://www.jstor.org/stable/23383308
Page Count: 6
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β-Glucuronidase from callus cultures of Scutellaria baicalensis Georgi was purified to apparent homogeneity by fractionated ammonium-sulfate precipitation and chromatography on diethylaminoethyl-cellulose, hydroxylapatite and baicalin-conjugated Sepharose 6B. A 650-fold purification was obtained by this purification system. When subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis the purified protein migrated as a single band with a molecular mass of 55 kDa. We determined that the native enzyme has a molecular mass of 230 kDa using gel-filtration chromatography. These results suggested that the enzyme exists as a homotetramer composed of four identical 55-kDa subunits. The enzyme showed a broad pH optimum between 7.0 and 8.0. The Km values were 9 μM, 10 μM, 30 μM and 40 μM for luteolin 3′-O-β-D-glucuronide, baicalin, wogonin 7-O-β-D-glucoronide and oroxlin 7-O-β-D-glucuronide, respectively. The enzyme was most active with flavone 7-O-β-D-glucuronides.
Planta © 1995 Springer