Linked Life Data

7836457

Source:http://linkedlifedata.com/resource/pubmed/id/7836457

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1995-3-2
pubmed:abstractText
Several functions of the 70-kilodalton heat shock cognate protein (Hsc70), such as peptide binding/release and clathrin uncoating, have been shown to require potassium ions. We have examined the effect of monovalent ions on the ATPase activity of Hsc70. The steady-state ATPase activities of Hsc70 and its amino-terminal 44-kDa ATPase fragment are minimal in the absence of K+ and reach a maximum at approximately 0.1 M [K+]. Activation of the ATPase turnover correlates with the ionic radii of monovalent ions; those that are at least 0.3 A smaller (Na+ and Li+) or larger (Cs+) than K+ show negligible activation, whereas ions with radii differing only approximately 0.1 A from that of K+ (NH4+ and Rb+) activate to approximately half the turnover rate observed with K+. Single turnover experiments with Hsc70 demonstrate that ATP hydrolysis is 5-fold slower with Na+ than with K+. The equilibrium binding of ADP or ATP to Hsc70 is unperturbed when K+ is replaced with Na+. These results are consistent with a role for monovalent ions as specific cofactors in the enzymatic hydrolysis of ATP.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
3
pubmed:volume
270
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2247-50
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
How potassium affects the activity of the molecular chaperone Hsc70. I. Potassium is required for optimal ATPase activity.
pubmed:affiliation
Beckman Laboratories for Structural Biology, Stanford University School of Medicine, California 94305.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S.