Agkihpin, a novel SVTLE from Gloydius halys Pallas, promotes platelet aggregation in vitro and inhibits thrombus formation in vivo in murine models of thrombosis.

In previous work, a snake venom arginine esterase (SVAE), agkihpin from the venom of Gloydius halys Pallas, was isolated and its biochemical data including Mr, PI, amino acid components and sugar content was collected. Here, the agkihpin was cloned and further characterized and we found that agkihpin could promote ADP-induced platelets aggregation, hydrolyze fibrin, cleave Aα and Bβ chains of fibrinogen and reduce the thrombosis induced by thrombin. Moreover, agkihpin hydrolyzed TAME with optimum temperatures at 30 °C-45 °C, and the hydrolysis was inhibited by EDTA, PMSF, DTT and promoted by Ca(2+), Fe(3+), Mg(2+), Zn(2+). The sequence features of agkihpin were detected as follows: the N-terminal residues was determined as I(V)L(Y)GDDECNINE by protein sequencing; the ORF was determined as 705 bp, and the deduced amino acid sequence was identified by peptide mass fingerprinting; the cysteines, cleavage sites, active sites and substrate binding sites of snake venom thrombin-like enzyme (SVTLE), were all conserved in amino acid sequence of agkihpin; 2 Leu(Tyr), 4 Asn and 121 Ile in amino acid sequence of agkihpin were first found in the amino acid sequences of SVTLEs. These findings indicated that agkihpin is a novel SVTLE. What's more, due to its several advantages of fibrino(gen)olytic and thrombosis-reduced activities, and devoid of bleeding risk, agkihpin may be developed into a thrombolytic drug in the future.