Purification and characterization of platelet aggregation inhibitors from snake venoms

Abstract

Proteins that inhibit glycoprotein (GP) IIb/IIIa mediated platelet aggregation have been purified from the venom of two snake species. A small platelet aggregation inhibitor (p1.AI), multisquamatin (Mr = 5,700), was purified from Echis multisquamatus venom by hydrophobic interaction HPLC and two steps on C18 reverse phase HPLC. A larger p1.AI, contortrostatin (Mr = 15,000), was purified by a similar HPLC procedure from the venom of Agkistrodon contortrix contortrix. Both p1.AIs inhibit ADP-induced human, canine and rabbit platelet aggregation using platelet rich plasma (PRP). Multisquamatin has an IC50 of 97 nM, 281 nM and 333 nM for human, canine and rabbit PRP, respectively. Contortrostatin has an IC50 of 49 nM, 120 nM and 1,150 nM for human, canine and rabbit PRP, respectively. In a competitive binding assay using 125I-7E3 (a monoclonal antibody to GPIIb/IIIa that inhibits platelet aggregation) both contortrostatin and multisquamatin demonstrated GPIIb/IIIa specific binding to human and canine platelets. The IC50 for contortrostatin displacement of 7E3 binding to human and canine GPIIb-/IIIa is 27 nM and 16 nM, respectively and for multisquamatin it is 3 nM and 63 nM, respectively. Our results indicate that both p1.AIs inhibit platelet aggregation by binding with high affinity to GPIIb/IIIa.

Insulin-like Growth Factor-I Receptor Mediates the Prosurvival Effect of Fibronectin

“…The adhesion assay was then performed as described previously (20) with minor changes. Briefly the adhesive cells were stained with crystal violet, and the optical density was measured at 550 nm.…”

A Novel Anti-tumor Protein from Calloselasma Rhodostoma Venom in Vietnam

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“…Therefore, since 2001, the scientific research collaboration between VN and University of Southern California (USC) was established. Since 2014 this project has been approved by VN government [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40]. …”

Purification, crystallization and preliminary X-ray analysis of the disintegrin contortrostatin fromAgkistrodon contortrix contortrixsnake venom

“…Contortrostatin has been isolated and puri®ed by a four-step HPLC procedure involving hydrophobic interaction HPLC, two steps of C 18 reverse-phase HPLC and cation-exchange HPLC (Trikha et al, 1994). The amino-acid sequence of contortrostatin has been determined recently (Zhou et al, 2000).…”

“…Contortrostatin (CN), a protein isolated from the venom of the southern copperhead snake Agkistrodon contortrix contortrix (Trikha et al, 1994), is a member of the disintegrin family of polypeptides. The disintegrins are small disul®de-rich RGD-containing (Arg-Gly-Asp recognition sequence-containing) peptides that bind to another class of proteins, integrins, which are intimately involved in cell-adhesion processes.…”