Linked Life Data

2159785

Source:http://linkedlifedata.com/resource/pubmed/id/2159785

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1990-6-20
pubmed:abstractText
PTPA, a specific phosphotyrosyl phosphatase activator of the PCSH2 and PCSL protein phosphatases, was purified up to apparent homogeneity from Xenopus laevis ovaries and rabbit skeletal muscle and highly purified from dog liver. PTPA appears as a 40-kDa protein in gel filtration, as well as in sucrose gradient centrifugation, and as a 37-39-kDa protein doublet in SDS-PAGE. Its estimated cellular concentration of 0.75 microM in oocytes or 0.25 microM in rabbit skeletal muscle is suggestive of an important role in the regulation of the cellular PTPase activity. The PTPase activation reaction of the PCSL phosphatase is time-dependent, ATP and Mg2+ being essential cofactors [A50(ATP) = 0.12 mM in the presence of 5 mM MgCl2]. With RCM lysozyme as substrate, the specific activity of the PTPA-activated PCSL phosphatase is 700 nmol of Pi/(min.mg). The pH optimum of the PTPase shifts from 8.5-9 in basal conditions to a neutral pH (7-7.5), and the A50 for the essential metal ion Mg2+ is decreased (3 mM). The activation is rapidly reversed in the presence of the substrate, and more slowly after removal of ATP.Mg. The PTPA-activated PCSL phosphatase represents a major PTPase activity in the cytosol of X. laevis oocytes (at least 50% of the measurable PTPase with RCM lysozyme phosphorylated on tyrosyl residues). The PTPA activation is specific for the PTPase activity of the PCSL and PCSH2 phosphatases, without affecting their phosphoseryl/threonyl phosphatase activity. However, effectors of the phosphorylase phosphatase activity, such as polycations and okadaic acid, also influence the PTPase activity. Phosphorylase alpha inhibits the activated PTPase activity (I50 = 5 microM). The PTPase activity of the other oligomeric PCS phosphatases (PCSH1 and PCSM) is not influenced, suggesting an inhibitory role for some of their subunits. This activation is compared with the recently described PTPase stimulation of the PCS phosphatases by ATP/PPi [Goris, J., Pallen, C. J., Parker, P. J., Hermann, J., Waterfield, M. D., & Merlevede, W. (1988) Biochem. J. 256, 1029-1034] and by tubulin [Jessus, C., Goris, J., Cayla, X., Hermann, J., Hendrix, P., Ozon, R., & Merlevede, W. (1989) Eur. J. Biochem. 180, 15-22].
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
23
pubmed:volume
29
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
658-67
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed-meshheading:2159785-4-Nitrophenylphosphatase, pubmed-meshheading:2159785-Adenosine Triphosphate, pubmed-meshheading:2159785-Animals, pubmed-meshheading:2159785-Drug Stability, pubmed-meshheading:2159785-Enzyme Activation, pubmed-meshheading:2159785-Hydrogen-Ion Concentration, pubmed-meshheading:2159785-Isoelectric Point, pubmed-meshheading:2159785-Liver, pubmed-meshheading:2159785-Magnesium, pubmed-meshheading:2159785-Manganese, pubmed-meshheading:2159785-Molecular Weight, pubmed-meshheading:2159785-Muscles, pubmed-meshheading:2159785-Oocytes, pubmed-meshheading:2159785-Phosphoprotein Phosphatases, pubmed-meshheading:2159785-Protein Tyrosine Phosphatases, pubmed-meshheading:2159785-Proteins, pubmed-meshheading:2159785-Rabbits, pubmed-meshheading:2159785-Substrate Specificity, pubmed-meshheading:2159785-Tubulin, pubmed-meshheading:2159785-Xenopus laevis
pubmed:year
1990
pubmed:articleTitle
Isolation and characterization of a tyrosyl phosphatase activator from rabbit skeletal muscle and Xenopus laevis oocytes.
pubmed:affiliation
Afdeling Biochemie, Faculteit Geneeskunde, Katholieke Universiteit te Leuven, Belgium.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't