Purification and renaturation of recombinant human lymphotoxin (tumour necrosis factor beta) expressed in Escherichia coli as inclusion bodies

High level expression of recombinant human tumour necrosis factor β (rh TNF-β) in Escherichia coli results in the formation of two portions of protein, namely soluble active protein and insoluble protein which is inactive and aggregates in the form of inclusion bodies (IBs). In this study, a procedure for purification and renaturation of rh TNF-β from inclusion bodies has been designed and verified experimentally with a product purity of more than 90% and a recovery of about 30%. The procedure includes washing of IBs with specific wash buffer (Triton X-100/EDTA/lysozyme/PMSF), their solubilization with 8 mol dm^?3 alkaline urea, purification with ion-exchange columns, refolding with renaturation buffer and finally concentration and desalination with an ultrafiltration membrane. The characteristics of the renatured protein were identical with those of purified protein from the soluble fraction as demonstrated by (1) SDS-PAGE, (2) cytotoxic activity on mouse L929 cells, (3) N-terminal amino acid sequence, and (4) gel filtration chromatography.     

合成基础油的性能与应用

综述了聚醚、合成烃、酯类油、磷酸酯、硅油及氟油等合成基础油的性能及其应用情况。     

DZX-2B型电子学综合实验装置常见故障与分析

介绍DZX-2B综合实验装置的组成、常见故障，及如何快速、准确的判断并排除故障的方法。     

Hot rolling of precision ring forgings

Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 11, pp. 33–35, November, 1992.