Adenosine triphosphatase (ATPase) is a hydrolase that catalyzes ATP synthesis, and is classified into membrane ATPase, myosin ATPase, and mitochondrial ATPase according to the activator, inhibitor, and enzyme localization used, with mitochondrial ATPase being the most abundant in the myocardium, followed by the liver, but harder to The mitochondrial ATPase of cardiomyocytes is opposite to myosin ATPase, activated by magnesium ions and inhibited by calcium ions; mitochondrial ATPase of hepatocytes can be activated by calcium and magnesium ions, and the staining solution is suitable for displaying the cardiac mitochondrial ATPase. ATPase hydrolyzes ATP in the following way: A-P-P-P + H2O → A-P-P + H3PO4 + energy Cardiac ATPase hydrolyzes ATP in the following way: A-P-P + H3PO4 + energy H3PO4 + energy

The principle of myocardial ATPase staining solution (magnesium activation method) is that myocardial ATPase is activated by magnesium ions, ATPase hydrolyzes the substrate ATP to ADP and phosphoric acid and releases energy, phosphoric acid binds with lead ions and forms colorless lead phosphate in the enzyme active site, which is then treated with sulfuric acid solution and transformed into brownish-black lead sulfide precipitate to show the color in the enzyme active site, and the magnesium activation method is suitable for displaying the ATPase in normal liver. ATPase is localized in the capillary bile ducts in normal liver, so it shows it especially clearly. In liver cancer or early damage of liver tissue, the capillary bile ducts are destroyed, and the ATPase activity decreases or disappears, which can be used as a symbol of damage to the liver cells, and this method can also show the Langerhans cells in the epidermis of the skin.