Linked Life Data

4020676

Source:http://linkedlifedata.com/resource/pubmed/id/4020676

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1985-9-17
pubmed:abstractText
The bioavailability of lead in kidney is mediated in part by binding to endogenous high-affinity cytosolic lead-binding proteins (PbBP), which are not detectable in liver. Addition of semipurified 11,500 dalton PbBP to liver delta-aminolevulinic acid dehydratase (ALAD) reaction mixtures reverses inhibition of this enzyme by lead and thus provides an explanation for the relative insensitivity of renal ALAD to lead inhibition in vivo and in vitro. This effect results in part from a marked increase in binding of 203Pb to the PbBP relative to control liver cytosol (no PbBP) as demonstrated by Sephadex G-150 gel filtration chromatography. Zinc is known to activate ALAD and is an endogenous component of the PbBP fraction (6 microM in reaction mixtures). Zinc activated hepatic and renal ALAD over a range of 1.5 to 50 microM and also reversed the IC50 lead-inhibited activity. Studies of zinc release and/or displacement from PbBP under ALAD assay conditions (37 degrees C, + glutathione, pH 6.8) were conducted utilizing Sephadex G-25 chromatography. Fifteen to twenty-five percent of the zinc in the PbBP fraction was released, and this value was not markedly influenced by addition of IC50 lead, temperature (4 degrees C) or absence of glutathione; however, zinc release was primarily dependent upon the pH of the reaction mixture. These data indicate that the PbBP fraction attenuates lead inhibition of ALAD in vitro both by chelating lead and apparently serving as a zinc donor for this enzyme under optimal conditions of the ALAD assay.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0022-3565
pubmed:author
pubmed:issnType
Print
pubmed:volume
234
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
365-71
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1985
pubmed:articleTitle
Mechanism of renal lead-binding protein reversal of delta-aminolevulinic acid dehydratase inhibition by lead.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.