Affiliation:
1. College of Pharmacy, University of Minnesota, 9–104 HSUF, 308 Harvard St. S.E., Minneapolis, MN 55455
2. Division of Colon and Rectal Surgery, Department of Surgery, Medical School, University of Minnesota, 516 Delaware Street S. E., Minneapolis, MN 55455, USA
Abstract
Abstract
The aim of this research is to characterize the presence of insulin-degrading enzyme in human colon and ileal mucosal cells. Biochemical studies, including the activity-pH profiles, the effects of enzyme inhibitors, immunoprecipitation and western blots, were conducted.
The majority of insulin-degrading activity in colon mucosal cells was localized in the cytosol. In both colon and ileum, cytosolic insulin-degrading activities had a pH optimum at pH 7.5, and were extensively inhibited by each of N-ethylmaleimide, p-chloromercuribenzoate, and 1,10-phenanthroline, but were very weakly affected by each of leupeptin, chymostatin, diisopropyl phosphofluoridate and soybean trypsin inhibitor. In the colon and ileum, more than 93% and 96%, respectively, of cytosolic insulin-degrading activities were removed by the mouse monoclonal antibody to human RBC insulin-degrading enzyme, as compared with less than 20% by the normal mouse IgG for both tissues. Further, a western blot analysis revealed that a cytosolic protein of 110 kD, in both human colon and ileum, reacted with the monoclonal antibody to insulin-degrading enzyme.
It is concluded that insulin-degrading enzyme is present in the cytosol of human colon and ileal mucosal cells.
Funder
Graduate School. University of Minnesota
Publisher
Oxford University Press (OUP)
Subject
Pharmaceutical Science,Pharmacology
Cited by
7 articles.
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