Affinity purification of renal dipeptidase solubilized with detergent

A new method is described for purification of the dehydropeptidase I enzyme, renal dipeptidase (EC 3.4.13.11). The six steps used are homogenization of the tissue, extraction with Triton X-100, sedimentation of insoluble material, and ion-exchange, size-exclusion, and affinity chromatographies. The use of Triton X-100 to solubilize the enzyme is a major advantage over the previously described procedure using n-butanol and results in both improvements in yield and interexperimental consistency. Also, the affinity column method we have employed results in higher recovery of active enzyme at the final step and a product which is apparently homogeneous. The method has general utility for this class of enzymes.