RESUMO

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.

Assuntos

Pulmão/enzimologia , Proteínas Tirosina Fosfatases/química , Animais , Bovinos , Inibidores Enzimáticos/farmacologia , Mononucleotídeo de Flavina/farmacologia , Cinética , Fosfatos/farmacologia , Proteínas Tirosina Fosfatases/efeitos dos fármacos , Proteínas Tirosina Fosfatases/metabolismo , Especificidade por Substrato , Vanadatos/farmacologia