Purification and characterization of a plasmin-like protease from Tenoderasinensis (Chinese mantis)

A novel type of protease (mantis egg fibrinolytic enzyme, MEF-2) was isolat ed from the egg cases of Tenodera sinensis. The protease was homogeneous by SDS-PAGE and its apparent molecular mass was 32,900 Da. The amino acids in the N-terminal region were Ile-Val-Gly-Gly-Glu-Glu-Ala-Val-Ala-Gly-Asp-Phe -Pro-Ile-Val-Ser-Leu-Gln-Glu. The enzyme was inhibited by PMSF, TLCK, aprot inin, benzamidine, soybean trypsin inhibitor and also slightly by elastatin al, EDTA, EGTA, cysteine and beta -mercaptoethanol. but TPCK, iodoacetate a nd E-64 did not affect the activity. MEF-2 was not sensitive to alpha (1)-a ntitrypsin but antithrombin III and alpha (2)-antiplasmin inhibited the enz yme. MEF-2 preferentially cleaved the oxidized B-chain of insulin between A rg(22) and Gly(23). Among chromogenic protease substrates, the most suscept ible to MEF-2 hydrolysis was benzoyl-Phe-Val-Arg-p-nitroanilide with maxima l activity at 30 degreesC and pH 5.0. These results indicate that MEF-2 bel ongs to the trypsin family. Upon incubation of crosslinked fibrin with MEF- 2, a steady increase of D-dimer suggests that the enzyme has a strong fibri nolytic activity. In conclusion, MEF-2 is a new type of proteolytic enzyme and has some potential for practical application in fibrinolysis. (C) 2001 Elsevier Science Ltd. All rights reserved.