enzyme that catalyzes the hydrolysis of the disaccharide maltose to the simple sugar glucose. The enzyme is found in plants, bacteria, and yeast; in humans and other vertebrates it is thought to be synthesized by cells of the mucous membrane lining the intestinal wall. During digestion, starch is partially transformed into maltose by the pancreatic or salivary enzymes called amylases; maltase secreted by the intestine then converts maltose into glucose. The glucose so produced is either utilized by the body or stored in the liver as glycogen (animal starch).