Protein phosphotyrosine phosphatases in Ascaris suum muscle.
Two forms of protein tyrosine phosphatases were partially purified from the musculo-cutaneous layer of Ascaris suum. A 50-55-kDa soluble form of the phosphatase cross-reacted with antisera raised against human PTP-1B and TC-PTP. Like the enzyme of human origin the phosphatase from Ascaris exhibited a preference for anionic substrates (tyrosine-phosphorylated carboxymethylated and maleylated lysozyme) and was inhibited by micromolar concentrations of vanadate, molybdate, Zn2+, heparin, and poly(Glu4Tyr). As revealed by immuno-cytochemistry, the phosphatase was mainly localized and appeared equally distributed in the cytoplasm, apart from the myofibrils, possibly in loose association with cytoskeletal elements. A second tyrosine phosphatase of 180 kDa molecular mass was mainly found in detergent extracts from a microsomal fraction. It showed no cross-reactivity with antisera raised against soluble mammalian phosphatases and dephosphorylated a basic substrate (Tyr-phosphorylated myelin basic protein). It was resistant to common inhibitors of mammalian tyrosine phosphatases except Zn2+ and thiol reagents.
Schmid
B
B
University of Konstanz, Faculty of Biology, Germany.
Wimmer
M
M
Tag
C
C
Hoffmann
R
R
Hofer
H W
HW
D000818:Animals; D017165:Ascaris suum / Q000201:enzymology*; D002458:Cell Fractionation; D003600:Cytosol / Q000201:enzymology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D007700:Kinetics; D008861:Microsomes / Q000201:enzymology; D008970:Molecular Weight; D009113:Muramidase / Q000378:metabolism; D009132:Muscles / Q000201:enzymology; D004676:Myelin Basic Protein / Q000378:metabolism; D017027:Protein Tyrosine Phosphatases / Q000032:analysis / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D013379:Substrate Specificity
D004791:Enzyme Inhibitors; D004676:Myelin Basic Protein; D017027:Protein Tyrosine Phosphatases; D009113:Muramidase