title: Studies on the meta and para O-sulphation of the catechol compound 3,4-dihydroxybenzoic acid by rat liver sulphotransferase in vitro.
abstract: The enzymic meta and para O-sulphation of 3,4-dihydroxybenzoic acid was investigated in vitro with a dialysed high-speed supernatant from rat liver. The O-sulphated products were identified by comparison with the reference compounds. The chemical synthesis and identification of the reference O-sulphate esters is described in detail. The sulphotransferase activity of the dialysed supernatant from rat liver towards 3,4-dihydroxybenzoic acid was 580 pmol of 3-O-sulphate and 120 pmol of 4-O-sulphate formed/min per mg of protein at the optimal pH of 7.4. The meta/para ratio of O-sulphation was independent of pH, time of incubation, concentration of enzyme and presence of dithiothreitol. The O-sulphate esters of 3,4-dihydroxybenzoic acid were found to be good substrates for the arylsulphatase reaction at pH 5.6. The arylsulphatase activity of a dialysed preparation from rat liver was 4.0 nmol of 3-O- and 5.7 nmol of 4-O-sulphate ester hydrolysed/min per mg of protein, respectively. Arylsulphatase from Helix pomatia had an activity of 620 pmol of 3-O-sulphate and of 16.6 nmol of 4-O-sulphate ester hydrolysed/min per unit (mumol/h) of sulphatase.
mesh_terms: D000818:Animals; D001192:Arylsulfatases / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D062385:Hydroxybenzoates / Q000138:chemical synthesis / Q000378:metabolism*; D066298:In Vitro Techniques; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008297:Male; D051381:Rats; D013463:Sulfuric Acid Esters / Q000138:chemical synthesis / Q000378:metabolism; D013466:Sulfurtransferases / Q000378:metabolism*
chemical_list: D062385:Hydroxybenzoates; D013463:Sulfuric Acid Esters; C009091:protocatechuic acid; D013466:Sulfurtransferases; D001192:Arylsulfatases