title: Kinetic characterization of bovine lung low-molecular-weight protein tyrosine phosphatase.
abstract: Protein tyrosine phosphatase is an important class of enzymes that plays an essential role in the cellular proliferation, differentiation, and oncogenesis. In this paper we report characterization of a low-molecular-weight protein tyrosine phosphatase purified from bovine lung. The enzyme activity was essentially independent of metal ions and sensitive to sulfhydryl reagents. Both vanadate and inorganic phosphate are competitive inhibitors, with Ki values of 0.38 microM and 0.28 mM, respectively. Besides p-nitrophenyl phosphate, the enzyme was also able to efficiently hydrolyze tyrosine phosphate, beta-naphthyl phosphate, and flavine mononucleotide.
authors.affiliation: Departamento de Bioquímica, Faculdade de Odontologia de Bauru, Universidade de São Paulo, Brasil.
authors.forename: M A
authors.initials: MA
authors.lastname: Buzalaf
authors.forename: E M
authors.initials: EM
authors.lastname: Taga
authors.forename: J M
authors.initials: JM
authors.lastname: Granjeiro
authors.forename: C V
authors.initials: CV
authors.lastname: Ferreira
authors.forename: V A
authors.initials: VA
authors.lastname: Lourenção
authors.forename: M M
authors.initials: MM
authors.lastname: Ortega
authors.forename: D W
authors.initials: DW
authors.lastname: Poletto
authors.forename: H
authors.initials: H
authors.lastname: Aoyama
mesh_terms: D000818:Animals; D002417:Cattle; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005486:Flavin Mononucleotide / Q000494:pharmacology; D007700:Kinetics; D008168:Lung / Q000201:enzymology*; D010710:Phosphates / Q000494:pharmacology; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism; D013379:Substrate Specificity; D014638:Vanadates / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D010710:Phosphates; D014638:Vanadates; D005486:Flavin Mononucleotide; D017027:Protein Tyrosine Phosphatases