fa بیوشیمی Biochemistry <p style="text-align: justify;"><em><strong>Background:</strong></em> Recombinant proteins overexpressed in E. coli are usually deposited in inclusion bodies. Cysteines in the protein contribute to this process. Inter- and intra- molecular disulfide bonds in chitinase, a cysteine-rich protein, cause aggregation when the recombinant protein is overexpressed in E. coli. Hence, aggregated proteins should be solubilized and allowed to refold to obtain native- or correctly- folded recombinant proteins.</p> <p style="text-align: justify;"><em><strong>Methods:</strong></em> Dilution method that allows refolding of recombinant proteins, especially at high protein concentrations, is to slowly add the soluble protein to refolding buffer. For this purpose: first, the inclusion bodies containing insoluble proteins were purified; second, the aggregated proteins were solubilized; finally, the soluble proteins were refolded using glutathione redox system, guanidinium chloride, dithiothreitol, sucrose, and glycerol, simultaneously.</p> <p style="text-align: justify;"><em><strong>Results: </strong></em>After protein solubilization and refolding, SDS-PAGE showed a 32 kDa band that was recognized by an anti-chitin antibody on western blots.</p> <p style="text-align: justify;"><em><strong>Conclusion: </strong></em>By this method, cysteine-rich proteins from E. coli inclusion bodies can be solubilized and correctly folded into active proteins.</p> 19 24 http://rbmb.net/browse.php?a_code=A-10-1-46&slc_lang=fa&sid=1 Malihe Moghadam 10031947532846006087 10031947532846006087 No Immunology Research Center, Medical School, Mashhad University of Medical Sciences, Mashhad, Iran Ali Ganji 10031947532846006088 10031947532846006088 No Immunology Research Center, Medical School, Mashhad University of Medical Sciences, Mashhad, Iran Abdolreza Varasteh 10031947532846006089 10031947532846006089 No Allergy Research Center, Medical School, Mashhad University of Medical Sciences, Mashhad, Iran Reza Falak 10031947532846006090 10031947532846006090 No Immunology Research Center, Iran University of Medical Sciences, Tehran, Iran - Department of Immunology, Iran University of Medical Sciences, Tehran, Iran Mojtaba Sankian sankianm@mums.ac.ir 10031947532846006091 10031947532846006091 Yes Immunology Research Center, Medical School, Mashhad University of Medical Sciences, Mashhad, Iran