Identification and characterization of Mg2+-dependent phosphotyrosyl protein phosphatase from rat liver cytosol.
Although highly purified preparations of Mg2+-dependent phosphoseryl protein phosphatase (also designated phosphatase IA or phosphatase 2C) dephosphorylated phosphotyrosyl histone, the activity has been resolved from phosphatase IA by polyacrylamide gel electrophoresis at pH 9.5. This novel phosphotyrosyl-specific protein phosphatase absolutely requires Mg2+ or Mn2+ for activity, is inhibited by Zn2+, vanadate and fluoride, and has an optimal pH of 9.0 and Mr = 50,000. Certain properties of this phosphatase so closely resemble those of phosphatase IA that the two enzymes tend to be copurified through various separation procedures.
D000818:Animals; D003600:Cytosol / Q000201:enzymology; D006657:Histones / Q000378:metabolism; D008099:Liver / Q000201:enzymology*; D008274:Magnesium / Q000494:pharmacology*; D010749:Phosphoprotein Phosphatases / Q000032:analysis / Q000302:isolation & purification*; D017027:Protein Tyrosine Phosphatases; D051381:Rats
D006657:Histones; D010749:Phosphoprotein Phosphatases; D017027:Protein Tyrosine Phosphatases; D008274:Magnesium