Linked Life Data

1499547

Source:http://linkedlifedata.com/resource/pubmed/id/1499547

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1992-9-16
pubmed:abstractText
A phosphoryl protein tyrosine phosphatase (PTPase) activity has been characterized in rat pancreatic acinar membranes using 32P-labeled poly(Glu,Tyr) as substrate. Acinar membranes exhibited a high affinity for the substrate, with an apparent Km of 0.46 microM and an apparent Vmax of 0.9 nmol.mg protein-1.min-1. Acinar membrane PTPase activity displayed specific characteristics of other PTPases; it was inhibited by the inhibitors Zn2+, orthovanadate and by the divalent cations Mn2+ and Mg2+, and was stimulated by the reducing-agent dithiothreitol. It was also inhibited by soybean trypsin inhibitor and stimulated by trypsin. Gel permeation of pancreatic acinar membranes gave a single peak of enzyme activity with an apparent molecular mass of 70 000 Da. Further purification by HPLC on DEAE revealed two peaks of PTPase activity at 120 mM and 180 mM NaCl. These two peaks reacted in a Western-blot procedure with anti-(peptide) serum directed towards conserved domain of PTPase as a common 67-kDa form associated with lower-molecular-mass proteolytic fragments (31-56 kDa). Incubation of pancreatic acini with somatostatin analogues, SMS 201-995 or BIM 23014, resulted in a stimulation of membrane PTPase activity. The stimulation was rapid and transient, with a maximal level reached within 15 min of addition. The two analogs stimulated PTPase activity in a dose-dependent manner with half-maximal activation occurring at 7 pM and 37 pM and maximal activation at 0.1 nM and 0.1-1 nM for SMS 201-995 and BIM 23014, respectively. The stimulated-membrane PTPase activity also eluted at an apparent molecular mass of 70 kDa in gel-permeation chromatography. The two analogs inhibited the binding of [125I-Tyr3]SMS 201-995 to pancreatic acinar membranes with similar relative potencies to that observed on stimulation of PTPase activity. We conclude that pancreatic acinar membranes possess a low-molecular-mass PTPase which is stimulated by somatostatin analogs at concentrations involving activation of membrane somatostatin receptors.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0014-2956
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
207
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1017-24
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed-meshheading:1499547-Amino Acid Sequence, pubmed-meshheading:1499547-Animals, pubmed-meshheading:1499547-Binding, Competitive, pubmed-meshheading:1499547-Blotting, Western, pubmed-meshheading:1499547-Cell Membrane, pubmed-meshheading:1499547-Cells, Cultured, pubmed-meshheading:1499547-Chromatography, Liquid, pubmed-meshheading:1499547-Electrophoresis, Polyacrylamide Gel, pubmed-meshheading:1499547-Enzyme Activation, pubmed-meshheading:1499547-Male, pubmed-meshheading:1499547-Membrane Proteins, pubmed-meshheading:1499547-Molecular Sequence Data, pubmed-meshheading:1499547-Octreotide, pubmed-meshheading:1499547-Pancreas, pubmed-meshheading:1499547-Peptides, Cyclic, pubmed-meshheading:1499547-Protein Tyrosine Phosphatases, pubmed-meshheading:1499547-Rats, pubmed-meshheading:1499547-Rats, Inbred Strains, pubmed-meshheading:1499547-Somatostatin
pubmed:year
1992
pubmed:articleTitle
Stimulation of a membrane tyrosine phosphatase activity by somatostatin analogues in rat pancreatic acinar cells.
pubmed:affiliation
Institut National de la Santé et de la Recherche Médicale U 151, CHU Rangueil, Toulouse, France.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't