Food Chemistry and Fish in Nutrition

6.5.5. Hydroperoxidases

They utilize hydrogen peroxide as a substrate. Two enzymes fall into this category (i) Peroxidase, (ii) Catalase.

(i) Peroxidase: It is found in milk and leukocytes and the prosthetic group is protoheme.  It catalyzes the reduction of hydrogen peroxide by the help of ascorbic acid, quinines and cytochrome C which act as electron acceptors.

(ii) Catalase: It is hemoprotein and found in blood and liver. It uses one molecule of H₂O₂ as a substrate electron donor and another molecule as electron acceptor.  Its function is to destroy H₂O₂ formed by the action of aerobic dehydrogenases.