Novel affinity support prepared by crosslinking purified insulin receptors to agarose

The insulin receptor interacts with other membrane proteins and possibly also a cytoplasmic second messenger(s) of insulin action. As an approach to identify and purify these ligands of the insulin receptor, we have developed an insulin receptor affinity support which retains the properties of the membrane associated insulin receptors. Insulin receptors first were purified from rat liver by affinity chromatography on wheat germ lectin agarose and insulin agarose. The purified insulin receptors then were crosslinked to agarose. The agarose immobilised insulin receptors had an affinity for insulin indistinguishable from the native receptors. In addition, insulin enhanced the autophosphorylation of the beta-subunit of these agarose immobilised insulin receptors. The insulin binding and autophosphorylation activities were stable for at least one week when this novel affinity support was stored at 4 degrees C.