Heme ligase (EC 4.99.1.8, heme detoxification protein, HDP, hemozoin synthase) is an enzyme with systematic name Fe3+:ferriprotoporphyrin IX ligase (β-hematin-forming). This enzyme catalyses the following reaction: 2 ferriprotoporphyrin IX beta-hematin This heme detoxifying enzyme is found in Plasmodium parasites.