The immunological demonstration of an association between maltase activity and proximal tubular cell borders in the rabbit kidney

Abstract

An immunological investigation has been made of the origin in the renal cortex of a membrane fraction selected for its high maltase activity, and also of the effect on the enzymatic activity of antibodies specifically directed against maltase. 1. 1. A particulate membrane fraction, isolated from rabbit renal cortex and carrying high specific activities of the disaccharidase enzymes maltase and trehalase, has been used to raise antibodies in guinea pigs. 2. 2. The antisera produced react with the remove from solution the soluble maltase activity which is released from the membrane fraction by papain. 3. 3. The immune precipitate exhibits unimpaired maltase activity. 4. 4. The antiserum when used in the indirect immunoflourescence technique on fixed sections of rabbit renal cortex reacts only with the apical area of the cells of the proximal tubules. This demonstrates that the membrane immunogens in general and the maltase in particular are confined to this bush border region.