Human a-Amylase enzyme is a digestive enzyme classified as a saccharidase (an enzyme that cleaves polysaccharides). The human alpha amylase(s) enzyme are calcium metalloenzymes, completely unable to function in the absence of calcium. By acting at random locations along the starch chain, human alpha amylase enzyme breaks down long-chain carbohydrates, ultimately yielding maltotriose and maltose from amylose, or maltose, glucose and "limit dextrin" from amylopectin. Because human salivary amylase can act anywhere on the substrate, human alpha amylase enzyme tends to be faster acting than beta amylase enzyme.