High-level expression, purification, and enzymatic characterization of truncated human plasminogen (Lys531-Asn791) in the methylotrophic yeast Pichia pastoris.
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ABSTRACT: Plasmin is a serine protease that plays a critical role in fibrinolysis, which is a process that prevents blood clots from growing and becoming problematic. Recombinant human microplasminogen (rh?Plg) is a derivative of plasmin that solely consists of the catalytic domain of human plasmin and lacks the five kringle domains found in the native protein. Developing an industrial production method that provides high yields of this protein with high purity, quality, and potency is critical for preclinical research.The human microplasminogen gene was cloned into the pPIC9K vector, and the recombinant plasmid was transformed into Pichia pastoris strain GS115. The concentration of plasmin reached 510.1 mg/L of culture medium. Under fermentation conditions, the yield of rh?Plg was 1.0 g/L. We purified rh?Plg to 96% purity by gel-filtration and cation-exchange chromatography. The specific activity of rh?Plg reached 23.6 U/mg. The K m of substrate hydrolysis by recombinant human microplasmin was comparable to that of human plasmin, while rh?Plm had higher k cat /Km values than plasmin. The high purity and activity of the rh?Plg obtained here will likely prove to be a valuable tool for studies of its application in thrombotic diseases and vitreoretinopathies.Reliable rh?Plg production (for use in therapeutic applications) is feasible using genetically modified P. pastoris as a host strain. The successful expression of rh?Plg in P. pastoris lays a solid foundation for its downstream application.
SUBMITTER: Liu R
PROVIDER: S-EPMC4460660 | biostudies-literature | 2015
REPOSITORIES: biostudies-literature
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