Phaseolamin, also known as "Phase 2", is a proteinaceous inhibitor of alpha-amylase. Originally isolate from white kidney beans, the protein is now commercially produced and sold as a diet aid. It works by inhibiting the action of starch degradation enzyme alpha-amylase, so that less sugar is absorbed in the small intestine. It is only active on alpha-amylases of animal origin, and does not affect those produced by plants, bacteria or fungi.