title: Evidence for a dipyrromethane cofactor at the catalytic site of E. coli porphobilinogen deaminase.
abstract: Porphobilinogen deaminase isolated from Escherichia coli is shown to contain a dipyrromethane cofactor (DPMC) linked covalently to the enzyme. The structure of the cofactor is proposed on the basis of its reaction with Ehrlich's reagent and from its chemical properties. The cofactor is involved in the binding of intermediates during the catalytic reaction but is not incorporated into the product preuroporphyrinogen, E. coli strains containing the cloned porphobilinogen deaminase gene (hemC) when grown on 5-amino[14C]-levulinic acid incorporate 14C radioactivity specifically into the dipyrromethane cofactor of porphobilinogen deaminase.
authors.affiliation: Department of Biochemistry, University of Southampton, England.
authors.forename: P M
authors.initials: PM
authors.lastname: Jordan
authors.forename: M J
authors.initials: MJ
authors.lastname: Warren
mesh_terms: D000642:Ammonia-Lyases / Q000378:metabolism*; D001547:Benzaldehydes; D001665:Binding Sites; D002384:Catalysis; D055598:Chemical Phenomena; D002621:Chemistry; D002851:Chromatography, High Pressure Liquid; D004926:Escherichia coli / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D011163:Hydroxymethylbilane Synthase / Q000378:metabolism*; D007202:Indicators and Reagents; D011162:Porphobilinogen / Q000378:metabolism; D011166:Porphyrins / Q000378:metabolism; D011758:Pyrroles / Q000378:metabolism*; D013053:Spectrophotometry
chemical_list: D001547:Benzaldehydes; D007202:Indicators and Reagents; D011166:Porphyrins; D011758:Pyrroles; C056776:dipyrromethane cofactor; D011162:Porphobilinogen; D011163:Hydroxymethylbilane Synthase; D000642:Ammonia-Lyases; C510241:p-dimethylaminobenzaldehyde