Purification and characterization of a O-methyltransferase capable of methylating 2-hydroxy-3-alkylpyrazine from Vitis vinifera L. (cv. Cabernet Sauvignon).
An S-adenosyl-L-methionine-dependent O-methyltransferase capable of methylating 2-hydroxy-3-alkylpyrazine (HP) was purified 7,300-fold to apparent homogeneity with an 8.2% overall recovery from Vitis vinifera L. (cv. Cabernet Sauvignon) through a purification procedure including column chromatography on DEAE-Sepharose FF, Ether-5PW, hydroxyapatite, G2000SW(XL), and DEAE-5PW. The relative molecular mass of the native enzyme estimated on gel permeation chromatography was 85 kDa, and the subunit molecular mass was estimated to be 41 kDa on SDS-polyacrylamide gel electrophoresis. The enzyme also methylates caffeic acid. The Vmax for IBHP and caffeic acid were 0.73 and 175 pkatals/mg, respectively, and the respective Km for IBHP and caffeic acid were 0.30 and 0.032 mm. The optimum pH for IBHP (8.5) was different from that for caffeic acid (7.5).
Hashizume
K
K
National Research Institute of Brewing, Higashihiroshima, Japan. hasidume@nrib.go.jp
Tozawa
K
K
Hiraga
Y
Y
Aramaki
I
I
D000595:Amino Acid Sequence; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011497:Protein O-Methyltransferase / Q000302:isolation & purification* / Q000378:metabolism; D011719:Pyrazines / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D027843:Vitis / Q000201:enzymology*
D011719:Pyrazines; D011497:Protein O-Methyltransferase