Properties and partial purification of the detergent-solubilized insulin receptor: a demonstration of negative cooperativity in micellar solution.

摘要: Abstract Turkey erythrocytes possess insulin receptors with binding properties very similar to those of mammalian receptors. In the present study, receptor avian erythrocyte has been solubilized in Triton X-100, extensively characterized and partially purified, its compared membrane-bound receptor. The a Stokes radius 70 A an apparent molecular weight 300 000 0.05% Triton. soluble was observed Thus, markedly temperature dependent for both forms, although kinetics were slower Both forms also showed sharp pH optimum; however, solubilization produced shift from maximal at 7.8 7.3. retained analog specificity, ion sensitivity negative cooperativity. did not appear degrade either bound or free insulin. On DEAE-cellulose chromatography eluted as single peak. specific activity this purified preparation 25–30 pmol/mg protein (about 500-fold enrichment over crude extract 5-fold highly membranes). Extensive attempts purify further by gel filtration, carboxymethyl-cellulose affinity resulted low yield only modest enrichment. Purification complicated because easily denatured; about 40% lost after 90-min exposure 3 M urea 4.5.