Separation of urine proteins on the anion-exchange resin mono Q

Proteins excreted in urine due to renal failure were separated on Mono Q, a new strong anion exchange designed for fast high-resolution protein separations. The separation procedure was divided into two steps. The first step involved removal of low-molecular-weight substances by rapid desalting on a Sephadex G-25 Superfine column. In the second step, the total protein fraction (3--6 ml) was loaded onto the Mono Q column with the aid of a superloop. The proteins were adsorbed onto the top of the ion-exchanger column and gradually displaced by a combined pH and salt gradient in 40 min. The choice of ion exchanger and initial operating conditions were based on data obtained from electrophoretic titration curve experiments. Identification of separated proteins was achieved by fused rocket electrophoresis and sodium dodecyl sulphate-polyacrylamide gel electrophoresis, respectively.