Linked Life Data

6951320

Source:http://linkedlifedata.com/resource/pubmed/id/6951320

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1982-6-24
pubmed:abstractText
Human placental estradiol 17 beta-dehydrogenase (E.C. 1.1.1.62) was inactivated at pH 6.3 by 3-bromo [2'-14C] acetoxy-1,3,5(10) estratrien-17-one, a know substrate. The affinity-alkylated enzyme was then hydrolyzed by trypsin. Radioactive peptides were initially isolated by gel filtration and identified according to which residue was alkylated. Tryptic peptides containing radioactive 3-carboxymethylhistidyl residues were further purified by cation-exchange chromatography. The population of these peptides varied, depending upon the conditions of enzyme inactivation. With 60 microM 3-bromo[2'-14]acetoxy-1,3,5 (10) estratrien -17-one four major peptides (a,b,c,d) each containing radioactive 3-carboxymethylhistidine, were eluted from the cation-exchange column. The alkylation of all of these peptides was completely suppressed when the enzyme was inactivated in the presence of excess estradiol-17 beta. The presence of equimolar NADPH during incubation greatly enhanced the alkylation of all four peptides. In the presence of NADPH, estradiol-17 beta most significantly decreased the formation of peptide d. Peptide d was the only peptide identified when the concentration of the alkylating steroid was lowered to 6 microM, a value approaching the Km. These observations indicate that peptide d is a histidyl-bearing peptide from the steroid-binding site which proximates the steroid A-ring. They further suggest that with the affinity labeling steroid at higher concentrations other nonspecific, hydrophobic sites on the enzyme are occupied and labeled.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0039-128X
pubmed:author
pubmed:issnType
Print
pubmed:volume
39
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
165-79
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1982
pubmed:articleTitle
Isolation of histidyl peptides of the steroid-binding site of human placental estradiol 17 beta-dehydrogenase.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't