Linked Life Data

7608900

Source:http://linkedlifedata.com/resource/pubmed/id/7608900

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
13
pubmed:dateCreated
1995-8-17
pubmed:abstractText
In a previous study, we described affinity labeling of the lamb uterine estrogen receptor by 17 alpha-[(bromoacetoxy)alkyl/alkynyl]estradiols. However, the intrinsic receptor-alkylating activities of these compounds were probably very hampered by their poor hydrolytic stability in estrogen receptor-containing tissue extracts. Therefore, (i) to develop affinity labels of the receptor not susceptible to hydrolysis and (ii) to specify the structural requirements for 17 alpha-electrophilic estradiol derivatives to be potent affinity labels of the receptor, we prepared four 17 alpha-[(haloacetamido)alkyl]estradiols. Three were bromoacetamides differing at the alkyl substituent (methyl, ethyl, or propyl), and the last was an [(iodoacetamido)propyl]estradiol prepared under both nonradioactive and 3H-labeled forms. Although their affinities for the estrogen receptor were very low (from 0.008% to 0.02% that of estradiol), they appeared to be efficient affinity labels of the receptor due to their irreversible inhibition of [3H]estradiol specific binding in lamb uterine cytosol. The effect of the compounds was time-, pH-, and concentration-dependent, with > 50% and > 80% estrogen-binding sites inactivated at 0 degrees C and pH 8.5, for the less active and more active compounds, respectively; the corresponding IC50 values varied from approximately 20 nM to approximately 10 microM. The order of efficiency was [(bromoacetamido)methyl]estradiol < [(bromoacetamido)ethyl]estradiol << [(bromoacetamido)propyl]estradiol < [(iodoacetamido)propyl]estradiol. Affinity labeling was directly demonstrated by ethanol-resistant binding of [3H][(iodoacetamido)propyl]estradiol to the receptor. The irreversible inactivation of the hormone-binding site by the four haloacetamides was prevented by treatment of the cytosol with the thiol-specific reagent methyl methanethiosulfonate, suggesting that the target of these compounds was probably the -SH of cysteines. Negative results obtained with other 17 alpha-electrophilic estradiol derivatives suggested that affinity labeling of the receptor by such derivatives required a minimal distance, including at least four C-C or C-N bonds, between the steroid and the electrophilic carbon. We therefore concluded that target cysteines in the hormone-binding site were not in direct contact with the steroid but probably in the immediate neighborhood of the D ring of the bound steroid.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0022-2623
pubmed:author
pubmed:issnType
Print
pubmed:day
23
pubmed:volume
38
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2339-48
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Steroidal affinity labels of the estrogen receptor. 2. 17 alpha-[(Haloacetamido)alkyl]estradiols.
pubmed:affiliation
Centre de Recherche de l'INSERM, Montpellier, France.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't