Linked Life Data

9236105

Source:http://linkedlifedata.com/resource/pubmed/id/9236105

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1997-9-19
pubmed:abstractText
We analysed a model assuming that the G protein activation process is an enzyme catalysed reaction: (i) GGDP recognition, (ii) GDP release, (iii) GTP binding and (iv) activated GGTP (or betagamma followed by alphaGTP) release. This model suggests (1) that the agonists Kact value may decrease with increasing G protein expression. At low G protein concentrations, the agonists Kact value reflects binding to the 'low affinity state'. If the G protein concentration is saturating, the agonists Kact values are correlated but not identical to their KD values for the 'high affinity state' observed in binding studies. (2) All the G proteins recognized by a receptor behave as competitive antagonists with respect to each other. (3) Overexpression of G proteins which recognize only the active receptor state may result in constitutive receptor activation. The rate of G protein activation can be accelerated by facilitating G protein recognition, by increasing the rate of GDP release, or by activating G protein release. Our model explains why guanyl nucleotides are essential for G proteins activation yet inhibit agonist binding, and why the ability of receptor ligands to simulate G protein activation is not always correlated with their ability to distinguish two receptor states, at equilibrium. It can also explain the inhibitory effects of GDP and of the G protein betagamma subunit.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0022-5193
pubmed:author
pubmed:issnType
Print
pubmed:day
7
pubmed:volume
187
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
15-37
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Seven helix receptors are enzymes catalysing G protein activation. What is the agonist Kact?
pubmed:affiliation
Laboratoire de Chimie Biologique et de la Nutrition, Faculty of Medicine, Université Libre de Bruxelles, Building G/E, CP 611, 808 Route de Lennik, Brussels, B-1070, Belgium.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't