The NSILA-s receptor in liver plasma membranes. Characterization and comparison with the insulin receptor.

摘要: NSILA-s (nonsuppressible insulin-like activity, soluble in acid ethanol) is a serum peptide that has and growth-promoting activities. We have demonstrated previously liver plasma membranes possess separate receptors for insulin characterized the receptor detail. In present study we properties specificity of compared them to those same tissue. Both 125I-NSILA-s 125I-insulin bind rapidly reversibly their membranes; maximal binding occurs at 20 degrees while seen 1-4 degrees. The pH optimum broad (6.0 8.0), contrast very sharp (7.5 8.0) binding. exhibit high degree specificity. With receptor, analogues compete proportion potency: greater than proinsulin NSILA-s. most potent order reversed: insulin. Furthermore, six preparations which varied 70-fold biological activity competed potencies. had been inactivated biologically by reduction aminoethylation growth hormone were less 1/100,000 as purified preparation. Purified fibroblast factor, epidermal nerve somatomedins B C 1% effective competing suggesting these factors act through other receptors. contrast, somatomedin A was 10% active multiplication-stimulating fully receptor. Analysis data suggests there are approximately 50 times more per cell, apparent affinity somewhat higher