Purification and characterization of a protein tyrosine acid phosphatase from boar seminal vesicle glands.
A protein tyrosine phosphatase (PTPase) with acid phosphatase activity was purified (500-fold) from the fluid of boar seminal vesicles. Preparative purification was performed with a 3-step procedure, employing FPLC S-Sepharose Fast Flow, Mono Q and Superdex 75 column. Protein tyrosine acid phosphatase (PTAPase) was homogeneous by polyacrylamide gel electrophoresis (PAGE, SDS-PAGE). PTAPase is a glycoprotein which has a molecular weight of about 41-42 kDa. This enzyme was maximally active at pH 5.5, and its thermostability was less than 80 degrees C. The K(m) value for p-nitrophenylphosphate, a specific synthetic substrate, was 0.87 x 10(-3)M, however, higher substrate specificity was shown when phosphotyrosine (K(m)=0.37 x 10(-3)M) and protein fragments, such as gastrin (K(m)=0.0032 x 10(-3)M) and hirudin (K(m)=0.0075 x 10(-3)M), were used as substrates. Activity of PTAPase was inhibited by dephostatin, molybdate and orthovanadate by 100, 95 and 70%, respectively, when phosphotyrosine was used as the substrate. Immunofluorescence study has shown that the seminal vesicles are the only source of PTAPase in boar seminal plasma.
Wysocki
P
P
Department of Animal Biochemistry, Faculty of Animal Bioengineering, University of Warmia and Mazury, 10-718 Olsztyn, Poland.
Strzezek
J
J
D000135:Acid Phosphatase / Q000302:isolation & purification* / Q000378:metabolism; D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel / Q000662:veterinary; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008297:Male; D008970:Molecular Weight; D017027:Protein Tyrosine Phosphatases / Q000302:isolation & purification* / Q000378:metabolism; D012669:Seminal Vesicles / Q000201:enzymology*; D013379:Substrate Specificity; D013552:Swine / Q000378:metabolism*; D013696:Temperature
D000135:Acid Phosphatase; D017027:Protein Tyrosine Phosphatases