Identification, purification, and characterization of phosphotyrosine-specific protein phosphatases from cultured chicken embryo fibroblasts

Journal Article · Fri Jun 01 04:00:00 EDT 1984 · Mol. Cell. Biol.; (United States)

DOI:https://doi.org/10.1128/MCB.4.6.1003· OSTI ID:6307548

Nelson, R L; Branton, P E

Tyrosine phosphorylation catalyzed by a unique class of protein kinases is an important process in both normal cell proliferation and oncogenic transformation. In this study, phosphoprotein phosphatases specific for the dephosphorylation of phosphotyrosine residues were partially purified from secondary chicken embryo fibroblasts, using /sup 32/P-labeled immunoglobulin G. The soluble activity was purified by using DEAE-cellulose and carboxymethyl cellulose column chromatography and gel filtration, and at least three enzyme species of apparent Mr 55,000 (pTPI), 50,000 (pTPII), and 95,000 (pTPIII) were resolved. All three enzymes possessed somewhat similar properties. They had a pH optimum of about 7.4, they were inhibited by Zn/sup 2 +/, vanadate, ATP, and ADP, and they were unaffected by divalent metal cations, EDTA, and F/sup -/ under standard assay conditions employing a physiological ionic strength. These properties suggest that they represent a class of enzymes distinct from well-known phosphoseryl-phosphothreonyl-protein phosphatases and that dephosphorylation of phosphotyrosine-containing proteins may be carried out by a unique family of phosphoprotein phosphatases. Transformation by Rous sarcoma virus resulted in a small increase in phosphotyrosyl-protein phosphatase activity.

• Research Organization: McMaster Univ., Hamilton, Ontario, Canada
• OSTI ID: 6307548
• Journal Information: Mol. Cell. Biol.; (United States), Journal Name: Mol. Cell. Biol.; (United States) Vol. 4:6; ISSN MCEBD
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMAL CELLS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMISTRY
CARBOXYLIC ACIDS
CHEMISTRY
CONNECTIVE TISSUE CELLS
DAYS LIVING RADIOISOTOPES
EMBRYONIC CELLS
ENZYME ACTIVITY
ENZYMES
ESTERASES
FIBROBLASTS
GLOBULINS
HYDROLASES
IMMUNOGLOBULINS
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
MICROORGANISMS
MOLECULAR WEIGHT
NUCLEI
ODD-ODD NUCLEI
ONCOGENIC TRANSFORMATIONS
ONCOGENIC VIRUSES
ORGANIC ACIDS
ORGANIC COMPOUNDS
PARASITES
PHOSPHATASES
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PROTEINS
RADIOISOTOPES
SOMATIC CELLS
VIRUSES