In vivo association of [125I]-insulin with a cytosolic insulin-degrading enzyme: detection by covalent cross-linking and immunoprecipitation with a monoclonal antibody.

Abstract

A cytosolic insulin-degrading enzyme (Mr = 110,000) was found to be cross-linked to [125I]-insulin in intact human hepatoma cells, HepG2, incubated with the hormone and treated with the bifunctional cross-linker, disuccinimidyl suberate. The labeling of this protein was greatly increased by concurrent treatment of the cells with N-ethylmaleimide, to the extent that the amount of [125I]-insulin cross-linked to the enzyme in these cells was approximately 20 to 50% that cross-linked to the insulin receptor. The labeling of the insulin-degrading enzyme required the prior interaction of [125I]-insulin with its receptor as well as a temperature- and energy-dependent processing of the hormone. The present work therefore supports a role for this protease in the cellular processing of insulin.

• Authors: J Hari, K Shii, R A Roth
• Journal: Endocrinology (Endocrinology) Vol. 120 Issue 2 Pg. 829-31 (Feb 1987) ISSN: 0013-7227 [Print] United States
• PMID: 3026782 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Antibodies, Monoclonal
• Cross-Linking Reagents
• Insulin
• Succinimides
• insulin, iodo-
• Peptide Hydrolases
• Insulysin
• disuccinimidyl suberate

Topics

• Antibodies, Monoclonal
• Carcinoma, Hepatocellular (enzymology)
• Cell Line
• Cross-Linking Reagents
• Cytosol (enzymology)
• Humans
• Insulin (analogs & derivatives, metabolism)
• Insulysin (metabolism)
• Liver Neoplasms (enzymology)
• Peptide Hydrolases (metabolism)
• Protein Binding
• Succinimides (pharmacology)