RECONSTITUTION OF THE SOLUBILIZED INSULIN-RECEPTOR IN PHOSPHOLIPID-VESICLES

The insulin receptor was solubilized from turkey erythrocyte membranes by extraction with 1% βoctylglucopyranoside. Insulin binding was enhanced when the solubilized material was reconstituted in phospholipid vesicles. The affinity of the reconstituted vesicles for various insulins was similar to that of the intact membranes: porcine insulin > proinsulin > desoctapeptide insulin. A curvilinear Scatchard plot was obtained for insulin binding to the reconstituted system at 15d̀C. A high affinity association constant of 1.4 X 109 M-1 was obtained from the Scatchard plot. This is a four-fold increase over the value for the turkey erythrocyte membrane, which contains more highly saturated phospholipids. This suggests that the insulin receptor may be sensitive to the lipid composition of the membranes in which it is embedded. © 1979 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.