L. Concentrates Ab, remove salt by dialysis. Need 0.75 ml caprylic acid to 10 ml rabbit serum. Crude step for IgG purification. DEAE cellulose or ammonium sulfate precipitate. Separates proteins on the basis of surface charge.
Proteins electrostatically bind onto a matrix bearing the opposite charge.
Elute proteins by a change in the pH or increase the concentration of the buffer. Anion exchange resin used for positive and negative selection of Ab. Ab has a basic isoelectric point when compared to most of the proteins in serum. Reuse regenerated resin. Good yield and purity from ascites and sera.