Refolding of lactate dehydrogenase by zeolite beta.

We used zeolite beta as an adsorbing matrix to refold recombinant lactate dehydrogenase (LDH) protein collected as an insoluble aggregate from a bacterial expression system. The adsorption isotherm revealed that 1 g of zeolite adsorbed 200 mg of denatured LDH solubilized with a buffer containing 6 M of guanidine hydrochloride. The pH of the buffer had little effect on the adsorption, but this property was abolished by preincubation of the zeolite with polyethylene glycol (PEG) in a weight ratio of 1:10.

Use of zeolite to refold a disulfide-bonded protein.

Zeolites are microporous crystalline aluminosilicates with a highly ordered structure. Using zeolite beta as an adsorbent, denatured/reduced hen egg lysozyme was refolded to the active form at high concentrations. The denatured/reduced lysozyme was adsorbed onto the zeolite and the protein was refolded by desorbing it into refolding buffer, consisting of redox reagents, guanidine hydrochloride, polyethylene glycol, and L-arginine.