Linked Life Data

16023486

Source:http://linkedlifedata.com/resource/pubmed/id/16023486

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2005-7-18
pubmed:abstractText
Cdc25s, dual-specificity phosphatases that dephosphorylate and activate cyclin-dependent kinases, are important regulators of the eukaryotic cell cycle. Herein, we probe the protonation state of the phosphate on the protein substrate of Cdc25 by pH-dependent studies and thiosubstitution. We have extended the useable range of pH for this enzyme substrate pair by using high concentrations of glycerol under acidic conditions. Using the protein substrate, we find a slope of 2 for the acidic side of the bell-shaped pH-rate profile, as found with other protein tyrosine phosphatases. Using thiophosphorylated protein substrate, we find no change in the basic side of the pH-rate profile, despite a large reduction in activity as measured by kcat/Km (0.18%) or kcat (0. 11%). In contrast, the acidic side of the profile changes shows a slope of 1, consistent with the 1.5 pH unit shift associated with thiosubstitution. Thus, Cdc25, like other protein phosphatases, uses a dianionic phosphorylated substrate.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0045-2068
pubmed:author
pubmed:issnType
Print
pubmed:volume
33
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
264-73
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Reactivity of Cdc25 phosphatase at low pH and with thiophosphorylated protein substrate.
pubmed:affiliation
Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA. rudolph@biochem.duke.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, N.I.H., Extramural