1. The behaviour of rat liver α-glucosidases on dextran gel (Sephadex G-100) columns was studied. A ‘retardation’ of an acid α-glucosidase activity was observed. This activity was identified as lysosome α-(1→4)-glucosidase. A single gel-filtration step resulted in a 700-fold purification of the enzyme. The same technique was also used to purify the acid α-glucosidase of human kidney. 2. The acid α-glucosidases of both tissues show very similar pH optima when tested with maltose or glycogen as substrate.
