CAT and coronary artery disorder: Cell-free hemoglobins have been extensively studied as artificial oxygen carriers for use in blood transfusions for hemorrhagic shock, anemia, ischemic heart diseases, etc. Following conjugation, it was discovered that the enzymatic activities of the SOD and CAT in the conjugates (Hb–SOD–CAT) retained more than 70% and 90% of their initial bioactivity, respectively [270].