TY - JOUR
T1 - A Chemical Model of Catechol-O-methyltransferase
T2 - Methylation of 3,4-Dihydroxybenzaldehyde in Aqueous Solution
AU - Sugata, Setsuro
AU - Ishihara, Shizuko
AU - (nee Tamano), Yuko Watanabe
AU - Nagata, Yoshiko
AU - Matsushima, Yoshikazu
PY - 1989
Y1 - 1989
N2 - The reaction of 3,4-dihydroxybenzaldehyde (LH2) and dimethylsulfate (DMS) to form the m- and /7-O-methyIated products (vanillin and isovanillin, respectively) in aqueous 2-(N-morpholino)ethane sulfonate buffer was studied kinetically. The products were determined by means of high-performance liquid chromatography. The 0-methylation occurred principally at the p-hydroxyl group in the absence of divalent metal ions. In the presence of Cu(II), the m-methylation was promoted and became predominant. Zn(II) showed a similar but less pronounced effect. The effects were explained in terms of the complex formation of LH2. The second order rate constants for the m- and p-methylation of the species, LH2, CuL and CuLf “by DMS were calculated. The values and their ratio for the i7f-//?-reactions increased in the order of LH2 < CuL < CuLf. The reaction may serve as a chemical model for catechol-0-methyltransferase, which requires divalent metals and catalyzes the m-methylation.
AB - The reaction of 3,4-dihydroxybenzaldehyde (LH2) and dimethylsulfate (DMS) to form the m- and /7-O-methyIated products (vanillin and isovanillin, respectively) in aqueous 2-(N-morpholino)ethane sulfonate buffer was studied kinetically. The products were determined by means of high-performance liquid chromatography. The 0-methylation occurred principally at the p-hydroxyl group in the absence of divalent metal ions. In the presence of Cu(II), the m-methylation was promoted and became predominant. Zn(II) showed a similar but less pronounced effect. The effects were explained in terms of the complex formation of LH2. The second order rate constants for the m- and p-methylation of the species, LH2, CuL and CuLf “by DMS were calculated. The values and their ratio for the i7f-//?-reactions increased in the order of LH2 < CuL < CuLf. The reaction may serve as a chemical model for catechol-0-methyltransferase, which requires divalent metals and catalyzes the m-methylation.
KW - (II) catechol-O-methyltransferase enzyme model 3
KW - 4-dihydroxybenzaldehyde dimethylsulfate vanillin isovanillin kinetics O-methylation metal chelate copper
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U2 - 10.1248/cpb.37.1143
DO - 10.1248/cpb.37.1143
M3 - Article
C2 - 2630085
AN - SCOPUS:0024362087
SN - 0009-2363
VL - 37
SP - 1143
EP - 1146
JO - Chemical and Pharmaceutical Bulletin
JF - Chemical and Pharmaceutical Bulletin
IS - 5
ER -