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O‐methylation of (+)‐(R)‐ and (−)‐(S)‐6,7‐dihydroxy‐1‐methyl‐1,2,3,4‐tetra‐hydroisoquinoline (salsolinol) in the presence of pig brain catechol‐o‐methyltransferase
Author(s) -
Hötzl Beate K.,
Thomas Helmut
Publication year - 1997
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/(sici)1520-636x(1997)9:4<367::aid-chir9>3.0.co;2-a
Subject(s) - chemistry , methylation , catechol o methyl transferase , catechol , methyltransferase , dopamine , in vitro , biochemistry , stereochemistry , membrane , high performance liquid chromatography , chromatography , dna , gene , allele , neuroscience , biology
(+)‐(R)‐ and (−)‐(S)‐salsolinol, dopamine‐derived tetrahydroisoquinolines, were tested as substrates of pig brain soluble and membrane‐bound catechol‐O‐methyltransferase (COMT) and as inhibitors of O‐methylation of dopamine by soluble COMT in vitro. Methylation products were separated by high‐performance liquid chromatography with electrochemical detection. Quantification of the products showed that O‐methylation of (+)‐(R)‐salsolinol by soluble COMT afforded the 7‐O‐methylated product salsoline preferentially, whereas (−)‐(S)‐salsolinol yielded almost equivalent amounts of the 6‐ and 7‐methyl ethers. Unlike O‐methylation by soluble COMT, 7‐O/6‐O‐methylation ratio produced by membrane‐bound COMT varied with (+)‐(R)‐salsolinol concentration. As to the O‐methylation of dopamine by soluble COMT, comparable competitive inhibition was observed with both (+)‐(R)‐ and (−)‐(S)‐salsolinol. Chirality 9:367–372, 1997. © 1997 Wiley‐Liss, Inc.