High performance in protease refolding by application of a continuous system using immobilized inhibitor

In the reoxidative refolding of Streptomyces griseus trypsin, which is a serine protease having three S-S bonds per molecule, a synthetic inhibitor immobilized on agarose beads was applied in order to avoid the digestion of non-renatured protease molecules by renatured ones. A semi-continuous refolding system was fabricated by packing such inhibitor-immobilized gels in a glass column and the optimal operating conditions were investigated. Taking account of the effective conditions surveyed in the system, a continuous refolding system was constructed and operated to achieve higher performance. By application of the continuous system, a marked increase in the recovery rate as well as high recovered activity could be accomplished, i.e., the recovery rate obtained was ca. 40 times higher than that in the semi-continuous system. This system was also revealed to be substantially advantageous since it includes not only effective refolding but also separation, purification and enrichment processes in one operation.