LAUSR

A nuclease from Yersinia enterocolitica subsp. palearctica (Nucyep) is a newly found thermostable nonspecific nuclease. The heat-resisting ability of this nuclease would be extremely useful in biological research or pharmaceutical production. However, the application of this nuclease is limited because of its poor yield. This research aimed to improve Nucyep productivity by producing a novel genetically engineered Escherichia coli and optimizing the production procedures. After 4 h of induction by lactose, the new genetically engineered E. coli can express a substantial amount of Nucyep in the form of inclusion bodies. The yield was approximately 0.3 g of inclusion bodies in 1 g of bacteria pellets. The inclusion bodies were extracted by sonication and solubilized in an 8 M urea buffer. Protein renaturation was successfully achieved by dilution method. Pure enzyme was obtained after subjecting to anion exchange. The Nucyep showed its nonspecific and heat resistant properties as previous report. Through quantification method, its activity was determined to be 1.3 × 106 K.U./mg. These results can serve as a reference for increasing Nucyep production.