TA-2, a thrombin-like enzyme from the Chinese white-lipped green pitviper (Trimeresurus albolabris)

Abstract

Through three chromatographic steps, a new thrombin-like enzyme (TLE), named TA-2, from the venom of the Chinese white-lipped green pitviper (Trimeresurus albolabris) has been isolated and purified to homogeneity. TA-2 was a single-chain glycoprotein with about 6% sugar, pI 3.9 and a molecular weight of 38.8 kD. Its N-terminal sequence (VVGGDECNIN) showed high sequence conformity with many other TLEs. In vitro, it coagulated bovine fibrinogen (108.6 NIH units/mg) and cleaved the Aα and Bβ chains of bovine fibrinogen-releasing fibrinopeptide A and B, but did not degrade bovine fibrin; displayed high stability at different temperature, pH, and presence of several divalent cations and inhibitors; also exhibited strong activity towards casein (192.3 units/mg) and high esterase activity upon Nα-p-tosyl-L-arginine methyl ester (11 units/mg); and behaved as a promoter to platelet aggregation induced by ADP or collagen. In vivo, TA-2 caused dose-dependent prolongation of bleeding time in mice, but had no hemorrhagic and edema-inducing activities even at high concentrations.

Isolation and Functional Characterization of Erythrofibrase: An Alfa-Fibrinogenase Enzyme from Trimeresurus erythrurus Venom of North-East India

“…Recombinant albofibrase also shows α-fibrinogenolytic activity, along with showing plasminogen activation similar to erythrofibrase [ 20 ]. Moreover, recombinant chitibrisin, GPV-TL1 and TA-2 shows fibrinogenolytic activity on both Aα and Bβ chains of plasminogen-free human fibrinogen, along with showing a variable extent of fibrinogen-clotting activity [ 31 , 32 , 33 ]. The Aα band-degradation activity of erythrofibrase is comparable to that of the band degradation pattern of plasmin, however, with very low potency.…”