Beta-cyclodextrin-bonded silica assists alkaline phosphatase and carbonic anhydrase refolding in a solid phase assisted refolding approach

The processes of protein refolding by artificial chaperones suffer from tedious steps of purifications which will finally affect the production costs. Replacement of the soluble stripping agent with immobilized beta-cyclodextrin or beta-cyclodextrin polymer beads might elevate some of these problems. Regarding this fact, we synthesized and evaluated various cyclodextrin-bonded silica particles to evaluate the refolding yields of denatured alkaline phosphatase and carbonic anhydrase. Our results indicated that refolding of denatured alkaline phosphatase raised from 30%, in the absence of chaperone, to about 65% in the presence of 70 mg/ml of the beta-cyclodextrin-bonded silica gel and to 74% in the concomitant presence of the new stripping agent and MgSO_4, a yield near to stripping by soluble beta-cyclodextrin. The refolding yield of carbonic anhydrase in the presence of beta-CD-bounded silica gel resin was significantly lower than the value obtained in the presence of soluble beta-CD (76% vs 54%). These data indicate that refolding of proteins by the silica gel immobilized beta-CD resin can be achieved though with lower yields. Regarding the high cost of downstream purification steps associated with soluble beta-CD, application of insoluble stripping agent might provide an alternative approach to cut down the industrial costs.