Insulin Receptor Purification
The insulin receptor is an integral membrane glycoprotein (Mr 300–350,000) consisting of two α subunits (Mr 130-135,000) and two β subunits (Mr 90-95,000) joined by disulfide bonds (Figure.1). The α subunit binds insulin and the β subunit contains tyrosine kinase activity and is autophosphorylated after insulin binding. Cloning of the human receptor (Ebina et al., 1985; Ullrich et al., 1985) has demonstrated that it is translated as a single-chain precursor of 1370 (Ullrich et al., 1985) or 1382 (Ebina et al., 1985) amino acids, containing the α and β subunits in tandem. It has been proposed that the subunits are formed by proteolytic cleavage at a tetra-peptide site [arg-lys-arg-arg] after posttranslational folding and inter-subunit disulfide bonding (Ullrich et al., 1985; Ebina et al., 1985).
KeywordsInsulin Receptor Wheat Germ Insulin Binding Acanthosis Nigricans Integral Membrane Glycoprotein
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