The use of a monoclonal antibody for the rapid purification of kidney neutral endopeptidase ("enkephalinase") solubilized in octyl glucoside

Abstract

The neutral endopeptidase ("enkephalinase") of the rabbit brush border membrane has been purified to homogeneity by a rapid immunoaffinity method using a monoclonal antibody. In contrast with other methods used so far, a complete extraction of enkephalinase from the brush border membrane can be achieved with octyl glucoside, without loss of activity. The solubilized enzyme can be selectively separated from the other proteins in a single step using an immunoaffinity column consisting of the monoclonal antibody covalently linked to Sepharose CL-4B. It is demonstrated that enkephalinase can then be recovered in an active form by elution at low pH. The purified enzyme obtained by this method is completely inhibited by thiorphan and appears as a single 94 000 dalton protein after polyacrylamide gel electrophoresis under denaturing and reducing conditions.