Linked Life Data

3283564

Source:http://linkedlifedata.com/resource/pubmed/id/3283564

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6168
pubmed:dateCreated
1988-6-9
pubmed:abstractText
Insulin is produced from an inactive precursor, proinsulin, through initial endoproteolytic cleavage at sites marked by pairs of basic amino-acid residues. We report here that lysates of insulin secretory granules contain two distinct Ca-dependent acidic endoproteases; one (type I) cleaving exclusively on the C-terminal side of Arg 31.Arg 32 (B-chain/C-peptide junction), the other (type II) preferentially on the C-terminal side of Lys 64.Arg 65 of proinsulin (C-peptide/A-chain junction). The Ca and pH requirements of these proteinases suggested that the type-II proteinase would be active in the Golgi apparatus and the secretory granule, whereas type-I activity would be compatible only with the intragranular environment. Kinetic analyses of (pro)insulin conversion intermediates in [35S]methionine-pulsed rat islets support this supposition. Our results suggest a simple mechanism whereby different dibasic sites can be cleaved in different cellular compartments. In conjunction with the regulation of the ionic composition of such compartments and the operation of post-Golgi segregation, our results also suggest how proteolytic conversion of diverse proproteins destined for different cellular sites can occur differentially and in a regulated manner.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0028-0836
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
333
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
93-6
pubmed:dateRevised
2009-9-29
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
Intraorganellar calcium and pH control proinsulin cleavage in the pancreatic beta cell via two distinct site-specific endopeptidases.
pubmed:affiliation
Department of Clinical Biochemistry, University of Cambridge, UK.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't