Disintegrins: The Naturally-Occurring Antagonists of Platelet Fibrinogen Receptor

Abstract

Disintegrins represent a family of low molecular weight, cysteinerich, RGD-containing peptides which inhibit fibrinogen binding to platelet membrane glycoprotein IIb/IIIa complex as well as other ligands to RGD-dependent integrins on the surface of other cells. Disintegrins occur in the venom of various vipers, and disintegrin-domains have been identified in viper venom hemorrhagins. Amino acid sequences of disintegrins are shown in comparing with those of RGD-containing non-disintegrins. The primary structure of disintegrins differs significantly from other fibrinogen receptor antagonists occurring in the venoms of Elapidae and leeches. Several aspects of structure-activity relationship of disintegrins, their biological activities and possible clinical applications are discussed.