Purification and characterization of the human protein tyrosine phosphatase, PTP mu, from a baculovirus expression system

Brady-Kalnay, S. M., Tonks, N. K. (November 1993) Purification and characterization of the human protein tyrosine phosphatase, PTP mu, from a baculovirus expression system. Molecular and Cellular Biochemistry, 128. pp. 131-141. ISSN 0300-8177

URL: http://www.ncbi.nlm.nih.gov/pubmed/7935345
DOI: 10.1007/BF01076764

Abstract

The receptor like PTPase, PTP mu, displays structural similarity in its extracellular segment to members of the immunoglobulin superfamily of cell adhesion molecules. The full length form of PTP mu (200 kD) and a construct expressing only the intracellular PTPase domain-containing segment (80 kD) were expressed in the baculovirus/Sf9 cell system, purified and characterized. Full length PTP mu was membrane associated while the truncated form was recovered in the soluble fraction. PTP mu preferentially dephosphorylated a reduced carboxamidomethylated and maleylated derivative of lysozyme (RCML) over other tyrosine phosphorylated substrates such as myelin basic protein (MBP) or the synthetic peptide EDNDYINASL. The enzymatic properties of the soluble, truncated form of the enzyme were examined in detail. The pH optimum was 7.5. It dephosphorylated RCML with a K-m of 400 nM and a V-max of 725 nmol/min/mg. This form of the enzyme was 2 fold more active than full length PTP mu. Trypsinization of the full length form inhibited activity. Vanadate and molybdate, potent tyrosine phosphatase inhibitors, abolished activity of the enzyme. Zn++ and Mn++ ions, polylysine, poly-glu/tyr, and spermine were also inhibitory.

Item Type: Paper
Uncontrolled Keywords: ADHESION BACULOVIRUS TYROSINE PHOSPHATASE PTP-MU IMMUNOGLOBULIN SUPERFAMILY CELL-ADHESION MOLECULE LEUKOCYTE COMMON ANTIGEN CYTOPLASMIC DOMAIN E-CADHERIN T-CELLS NG-CAM RECEPTOR KINASE REGION DROSOPHILA
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification
organism description > bacteria
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > enzymes
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein characterization
biotechnology > chromatography > protein purification
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > enzymes > protein tyrosine phosphatase
CSHL Authors:
Communities: CSHL labs > Tonks lab
Depositing User: Matt Covey
Date: November 1993
Date Deposited: 17 Dec 2013 17:49
Last Modified: 17 Dec 2013 17:49
Related URLs:
URI: http://repository.cshl.edu/id/eprint/29078

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