Linked Life Data

2010043

Source:http://linkedlifedata.com/resource/pubmed/id/2010043

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1991-5-6
pubmed:abstractText
The nature of insulin degradation within endosomes was studied in vitro. Radiolabeled insulin was perfused into rat liver via the portal vein, and insulin-containing endosomes were prepared by differential centrifugation. The endosomes were incubated in various buffers, and hormone degradation was monitored by Sephadex G-50 chromatography and high-performance liquid chromatography (HPLC). Endosomes incubated in simple imidazole or HEPES (pH 7.4) buffers rapidly degraded insulin to intermediate- and then to low-molecular-weight products that were lost from the vesicles. HPLC analysis of insulin-sized material showed the products to be the same as those produced by intact cells. The endosomes did not acidify in these buffers (as assessed by the acridine orange method), and ATP had no effects. When the endosomes were incubated in a chloride-containing buffer, degradation was greatly inhibited, and acidification did not occur. Both insulin degradation and acidification were activated when Mg-ATP was added to this buffer system. HPLC analysis of the products generated in this system revealed not only typical cellular products but additional less hydrophobic products. Western-blot analysis of endosomal protein with anti-insulin-degrading enzyme antibody showed this enzyme to be present. In conclusion, isolated endosomes rapidly and completely degrade insulin through products that are typical of cellular degradation without requiring acidification. Chloride-containing buffers inhibit endosomal degradation, which is reversed by Mg-ATP, but this system does not mimic cellular degradation. At least one of the enzymes responsible for insulin degradation is insulin-degrading enzyme.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0012-1797
pubmed:author
pubmed:issnType
Print
pubmed:volume
40
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
436-43
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Degradation of intraendosomal insulin by insulin-degrading enzyme without acidification.
pubmed:affiliation
Department of Internal Medicine, University of Nebraska Medical Center, Omaha 68198-3020.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S.