Glucose-forming amylase in human urine.

This paper describes the isolation and study of glucose-forming amylase existing in human urine as a normal component. After removing alpha-amylase [EC 3.2.1.1] by adsorption onto raw starch, urine was treated with DEAE-cellulose and Bio Gel P-150, and three fractionated proteins (F-1, F-2, and F-3), isolated in a homogeneous state by gel filtration, were shown to display glucose-formine amylase activity. They all hydrolyzed starch and glycogen, releasing glucose as the sole product, and also hydrolyzed maltose. However, their molecular weights, as estimated by gel filtration, isoelectric points, stabilities, and several enzymatic properties were different. The implications of the results are discussed.