Linked Life Data

12397389

Source:http://linkedlifedata.com/resource/pubmed/id/12397389

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2002-10-24
pubmed:abstractText
Urea, at concentrations routinely observed in the renal inner medulla during antidiuresis in many mammals, is a potent protein destabilizing agent that reduces the activity of many enzymes. The molecular chaperone heat shock protein 72 (HSP72) is expressed at about 5 ng/ micro g protein in the renal papilla and is thus 40 times more abundant than in the isosmotic cortex and may counteract the deleterious effects of high urea concentrations in the inner medulla. To test this hypothesis, we examined the effect of recombinant HSP72 on lactate dehydrogenase activity in the presence of 0.8 M urea in a cell-free system. The urea-induced increase in K(m) was reduced by 85% in the presence of 1 microM HSP72 but only by 6% by 100 mM betaine, a "counteracting" trimethylamine osmolyte. Conversely, the decrease in V(max) with 0.8 M urea was not affected by HSP72 but was attenuated by 42% in the presence of betaine. The protective effect of HSP72 was confirmed by the attenuation of the urea-induced decrease in the activity of another model enzyme, beta-galactosidase, by lysate of HSP72-overexpressing MDCK cells. Hence, in addition to the trimethylamine osmolytes, HSP72 may participate in counteracting urea-mediated effects on protein function in the renal papilla.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0031-6768
pubmed:author
pubmed:issnType
Print
pubmed:volume
445
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
67-73
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Heat shock protein 72, a chaperone abundant in renal papilla, counteracts urea-mediated inhibition of enzymes.
pubmed:affiliation
Dept of Physiology, University of Munich, Pettenkoferstrasse 12, 80336 München, Germany. W.Neuhofer@physiol.med.uni-muenchen.de
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't