Linked Life Data

2835083

Source:http://linkedlifedata.com/resource/pubmed/id/2835083

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1988-6-14
pubmed:abstractText
The effects of Mg2+ or ethylenediaminetetraacetic acid (EDTA) on 125I-glucagon binding to rat liver plasma membranes have been characterized. In the absence of guanosine 5'-triphosphate (GTP), maximal binding of 125I-glucagon occurs in the absence of added Mg2+. Addition of EDTA or Mg2+ diminishes binding in a dose-dependent manner. In the presence of GTP, maximal binding occurs in the presence of 2.5 mM Mg2+ (EC50 = 0.3 mM) while EDTA or higher concentrations of Mg2+ diminish binding. Response to exogenous Mg2+ or EDTA depends on the concentration of Mg2+ in the membranes and may vary with the method used for membrane isolation. Solubilized 125I-glucagon-receptor complexes fractionate on gel filtration columns as high molecular weight, GTP-sensitive complexes in which receptors are coupled to regulatory proteins and lower molecular weight, GTP-insensitive complexes in which receptors are not coupled to other components of the adenylyl cyclase system. In the absence of GTP, 40 mM Mg2+ or 5 mM EDTA diminishes receptor affinity for hormone (from KD = 1.2 +/- 0.1 nM to KD = 2.6 +/- 0.3 nM) and the fraction of 125I-glucagon in high molecular weight receptor-Ns complexes without affecting site number (Bmax = 1.8 +/- 0.1 pmol/mg of protein). Thus, while GTP promotes disaggregation of receptor-Ns complexes, Mg2+ or EDTA diminishes the affinity with which these species bind hormone. In the presence of GTP, hormone binds to lower affinity (KD = 9.0 +/- 3.0 nM), low molecular weight receptors uncoupled from Ns.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
23
pubmed:volume
27
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1111-6
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
Divalent cations regulate glucagon binding. Evidence for actions on receptor-Ns complexes and on receptors uncoupled from Ns.
pubmed:affiliation
Memorial Sloan-Kettering Cancer Center, New York, New York 10021.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.