Alpha Amylase used in conjunction with the Periodic Acid Schiff (PAS) Stain Kit is used to identify glycogen. PAS-positive entities and structures are also numerous in tissue sections. The most common application is for demonstrating glycogen in the liver. Duplicate sections are stained with or without alpha amylase, a glycogen-digesting enzyme. Comparing PAS signal intensity in a digested tissue sample with one that has not been digested will give an indication of the amount of glycogen present.