[Prokaryotic expression, purification and activity analysis of recombinant human serine protease inhibitor Hespintor...

Hespintor is an unknown function protein that was got from hepatoblastoma cell lines HepG2 by suppression subtractive hybridization technique (SSH), sequence analysis showed that the protein is a new member of secretory type of Kazal type serine protease inhibitor (Serpin) family, and has high homology with esophageal cancer related gene 2 (ECRG2). The coding sequence of Hespintor's Kazal domain was subcloned into prokaryotic expression vector pET-40b(+), then transformed into Rosetta (DE3). A recombinant protein about 42 kDa in the form of inclusion body was optimization expressed by inducing with 0.25 mmol/L IPTG, 30 degrees C for 5 h. and its specificity was confirmed via Western blotting. The recombinant protein was purified by metal chelate affinity chromatography (MCAC) and anion-exchange chromatography. The preliminary experimental result showed that the recombinant protein can inhibit trysin hydrolysis activity specifically. The result clearly demonstrated that Hespintor, as a novel member of Serpin, would be valuable in developing anti-tumor agents.