title: Purification, characterization and reaction mechanism of novel arylsulfotransferase obtained from an anaerobic bacterium of human intestine.
abstract: A novel type of arylsulfotransferase was purified from Eubacterium A-44, one of the predominant bacteria of human intestine. The enzyme (Mr 315 000) was composed of four identical subunits (Mr 80 000) whose N-terminal amino acids were arginine. pI and optimal pH of the enzyme were 3.9 and 8-9, respectively. The apparent Km for p-nitrophenylsulfate using tyramine as an acceptor substrate and that for tyramine using p-nitrophenylsulfate as a donor substrate were determined to be 0.104 mM and 3.5 mM, respectively. The reaction mechanism of the enzyme was proposed as follows: a donor substrate, p-nitrophenyl [35S]sulfate, combines a histidine residue of the enzyme active site with concomitant release of a phenolic compound, p-nitrophenol. The sulfate group of the histidine residue transfers to a tyrosine group, and then to an acceptor with the binding of another donor to the histidine residue.
authors.forename: D H
authors.initials: DH
authors.lastname: Kim
authors.forename: L
authors.initials: L
authors.lastname: Konishi
authors.forename: K
authors.initials: K
authors.lastname: Kobashi
mesh_terms: D001120:Arginine / Q000032:analysis; D015239:Arylsulfotransferase; D001665:Binding Sites; D005051:Eubacterium / Q000201:enzymology*; D006639:Histidine / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007422:Intestines / Q000382:microbiology*; D007526:Isoelectric Point; D046911:Macromolecular Substances; D008970:Molecular Weight; D009578:Nitrobenzenes / Q000378:metabolism; D013431:Sulfates / Q000378:metabolism; D013466:Sulfurtransferases / Q000302:isolation & purification*; D014439:Tyramine / Q000378:metabolism
chemical_list: D046911:Macromolecular Substances; D009578:Nitrobenzenes; D013431:Sulfates; C023379:4-nitrophenyl sulfate; D006639:Histidine; D001120:Arginine; D013466:Sulfurtransferases; D015239:Arylsulfotransferase; D014439:Tyramine