ISSN:
1432-0428
Keywords:
Insulin receptor
;
α-subunit
;
insulin binding
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Photoaffinity labelling of hepatic insulin receptors revealed specifically-labelled bands of 130, 90 and 40kDa. Endogenous protease activity in hepatic plasma membranes, as well as contaminating proteases present in preparations of clostridial collagenase, degraded some of the 130-kDa insulinbinding subunit to a 115-kDa form. However, a large proportion of the 130-kDa subunits were resistant to degradation, suggesting the presence of two classes of insulin receptor in hepatic plasma membranes. In one class the 130-kDa subunit was sensitive to proteolysis, while in the other it was not. In contrast, the 130-kDa receptor subunits of adipose tissue were all resistant to such degradation. Scatchard analysis of control and collagenase-treated plasma membranes demonstrated that conversion of the 130-kDa subunit to a 115-kDa form did not affect the insulin-binding characteristics of the receptor. It was also apparent that insulin binds to a single class of highaffinity sites in hepatic plasma membranes.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00265029
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