title: Identification of a molybdopterin-containing molybdenum cofactor in xanthine dehydrogenase from Pseudomonas aeruginosa.
abstract: Xanthine dehydrogenase has been purified from Pseudomonas aeruginosa cultured on a rich medium and induced with hypoxanthine. The enzyme was shown to contain FAD, iron sulfur centers and a molybdenum cofactor as prosthetic groups. Analysis of the molybdenum cofactor in this enzyme has revealed that the cofactor contains molybdopterin (MPT) rather than molybdopterin guanine dinucleotide or molybdopterin cytosine dinucleotide which have previously been identified in a number of molybdoenzymes of bacterial origin. The pterin cofactor in P.aeruginosa xanthine dehydrogenase was alkylated and the resulting product was identified as dicarboxamidomethyl molybdopterin. In addition, the pterin released from the enzyme by denaturation with guanidine-HCl was found to chromatograph on Sephadex G-15 with an apparent molecular weight of 350. These results document the first example of a bacterial enzyme with a molybdenum cofactor comprising molybdopterin and the metal only.
authors.affiliation: Department of Biochemistry, Duke University Medical Center, Durham, NC 27710.
authors.forename: J L
authors.initials: JL
authors.lastname: Johnson
authors.forename: M
authors.initials: M
authors.lastname: Chaudhury
authors.forename: K V
authors.initials: KV
authors.lastname: Rajagopalan
mesh_terms: D000818:Animals; D002645:Chickens; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D003067:Coenzymes / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D005182:Flavin-Adenine Dinucleotide / Q000378:metabolism; D008667:Metalloproteins / Q000737:chemistry*; D015394:Molecular Structure; D008982:Molybdenum / Q000737:chemistry*; D000090006:Molybdenum Cofactors; D011550:Pseudomonas aeruginosa / Q000201:enzymology*; D011621:Pteridines / Q000737:chemistry*; D013057:Spectrum Analysis; D014968:Xanthine Dehydrogenase / Q000737:chemistry*
chemical_list: D003067:Coenzymes; D005182:Flavin-Adenine Dinucleotide; D008667:Metalloproteins; D008982:Molybdenum; D000090006:Molybdenum Cofactors; D011621:Pteridines; D014968:Xanthine Dehydrogenase; C022261:molybdopterin