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Purification and characterization of the human brain insulin receptor.

1986; Elsevier BV; Volume: 261; Issue: 8 Linguagem: Inglês

10.1016/s0021-9258(17)35711-3

1083-351X

Richard A. Roth, David O. Morgan, Jacqueline Beaudoin, V. R. Sara,

Diabetes and associated disorders

The insulin receptor from human brain cortex was purified by a eo~bination monoclonal antibody affinity column and a wheat germ agglutinin column.This purified receptor preparation exhibited major protein bands of apparent M, = 135,000 and 95,000, molecular weights comparable to those for the a and , i ? subunits of the purified human placental and rat liver receptors.A minor protein band of apparent M, = 120,000 was also observed in the brain receptor preparation.Crosslinking of '251-insulin to all three receptor preparations was found to preferentially label a protein of apparent M, = 135,000.In contrast, cross-linking of 12%labeled insulin-like growth factor I to the brain preparation preferentially labeled the protein of apparent M, = 120,000, The purified brain insulin receptor was found to be identical with the placental insulin receptor in the amount of neuramini~~e-sensitive sialic acid and reaction with three monoclonal antibodies to the , f ? subunit of the placental receptor.In contrast, a monoclonal antibody to the insulin binding site recognized the placental receptor approximately 300 times better than the brain receptor.These results indicate that the brain insulin receptor differs from the receptor in other tissues and suggests that this difference is not simply due to the amount of sialic acid on the receptor.