Hementin is an anticoagulant protease from the salivary glands of the giant Amazon leech. Hementin is a calcium-dependent protease with a molecular weight of 80–120 kDa, and it contains 39 amino acid sequences. Hementin is present in both the anterior and posterior salivary glands, however it is mostly produced from certain cells in the anterior glands. The secretion of hementin is limited to the lumen of the proboscis, which the Amazon leech inserts into the host to suck blood. Hementin dissolves platelet-rich blood clots and lets the blood flow through the proboscis. Hementin is able to dissolve a type of blood clots that cannot be dissolved by other compounds, such as streptokinase and urokinase.