Linked Life Data

3941079

Source:http://linkedlifedata.com/resource/pubmed/id/3941079

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1986-2-12
pubmed:abstractText
The synthetic peptide, L-Val-L-Tyr-L-Pro-L-isoAsp-Gly-L-Ala, is a substrate for the erythrocyte and brain protein carboxyl methyltransferases. These enzymes catalyze the methyl esterification of the free alpha-carboxyl group of the isoaspartyl residue, to which the glycyl residue is linked through the side chain beta-carboxyl group. In this work, we show that the alpha-methyl ester of this peptide was rapidly demethylated (t1/2 = 4 min at 37 degrees C, pH 7.4) in erythrocyte cytosolic extracts and that the product of this reaction appears to be the succinimide ring derivative of the peptide. The rate of demethylation, measured at either pH 6.0 or 7.4, was the same in buffer and erythrocyte extracts, suggesting that succinimide formation was a nonenzymatic reaction. The L-succinimide is more stable than the ester, but can be hydrolyzed in buffer at pH 7.4 (t1/2 = 180 min at 37 degrees C) to give a mixture of about 75% isoaspartyl peptide and 25% normal aspartyl peptide. The metabolism of the succinimide hexapeptide in erythrocyte extracts appears to be more complex, however. The implications of this work for the methylation and demethylation of cellular proteins containing structurally altered aspartyl residues are discussed.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
261
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
306-12
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1986
pubmed:articleTitle
Metabolism of a synthetic L-isoaspartyl-containing hexapeptide in erythrocyte extracts. Enzymatic methyl esterification is followed by nonenzymatic succinimide formation.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't