Optimized Expression of Snake Fibrinolytic Enzyme Alfimeprase in Pichia pastoris and Its Activity Identification / 中国生物工程杂志

Alfimeprase(ALF)is a recombinantly modified variant of non-hemorrhagic zinc metalloproteinase fibrolase.The target gene alf was obtained from the clone vector p43-alf and cloned into the Pichia pastoris expression vector pPICZ? A.Through high efficiency transformation and Zeocin selection,the recombinant strains of pPICZ?A-alf /GS115 were isolated.In order to achieve a high level expression of recombinant Alfimeprase(rALF),optimization of pH value,methanol daily addition concentration,cell density and methanol induction time points were carried out,and the production of rALF reached up to 425 mg/L.By His?Bind chromatography,the purity of secreted rALF was as high as 95 %.SDS-PAGE and Western blot analysis show that rALF has a molecular weight of about 24 kDa and is bound specifically to anti-His?tag monoclonal antibody.Activity identification results of the modified fibrin plate method demonstrate that the secreted rALF has high fibrinolytic activity.Thus sets up an optimized expression system for ALF,which will play an important role in its further studies and industrial production.

Soluble Expression and Purification of Snake Venoms Fihrino(geno)lytic Emzyme Alfimeprase in E.coli / 中国生物工程杂志

Fibrolase is a non-hemorrhagic zinc metalloproteinase isolated from southern copperhead snake venom (Agkistrodon contortrix contortrix) and is capable of degrading fibrin clots resulting from purified fibrinogen or from blood plasma. Alfimeprase, a truncated form of fibrolase, as a clinical agent was successfully completed PhaseII clinical trials.The cDNA of alfimeprase was amplified by recursive PCR, digested with BamHI and HindII, and cloned into pET43.1a, pMALp2X and pMALc2X vectors to generate fusions with NusA, MBP and sMBP(with signal peptide), respectively. Nus/alfimeprase was expressed in soluble form by co-expressing with chaperone FkpA and inducing with1mmol/L IPTG. The fusion protein accounted for about 25 % of total protein following cell lysis. Alfimeprase was successfully purifiesd by Ni-NTA affinity chromatography and cleaved by enterokinase. The results demonstrate the fibrinolytic activity of recombinant alfimeprase using fibrin plate assays and fibrinogen hydrolysis.