Function and induction of the microsomal heme oxygenase

The microsomal heme oxygenase system consists of heme oxygenase and NADPH-cytochrome P-450 reductase, and is considered to play a key role in the physiological heme catabolism to yield biliverdin in animals. Heme oxygenase purified from either pig spleen or rat liver has a minimum molecular weight of 32 000, and binds heme to form a l:1 complex which exhibits properties resembled to those of hemoglobin and myoglobin. Heme degradation in the heme oxygenase reaction proceeds essentially as a series of autocatalytic oxidation of heme which is bound to heme oxygenase. The possible mechanism of heme degradation in the heme oxygenase reaction was presented.