Iron in catalase

Catalase is a high-efficient enzyme for the degradation of hydrogen peroxide into water and molecular oxygen, mainly expressed in cytoplasm, peroxisomes and in mitochondria.

Although catalase is generally distributed in nearly all living tissues its concentration varies enormously from tissue to tissue. In mammals the greatest quantity occurs in the liver and in the erythrocytes.

Protoporphyrin IX

Iron is introduced into both hemoglobin and catalase at the time erythrocytes are form and this iron remains firmly bound for the lifetime of the red cell.

The iron appears to be present only in the ferric form and cannot be reduced chemically by any procedure that does not denature the enzyme.

Catalase contains four identical subunits each quipped with a high-spin Fe (III)-protoporphyrin IX (7-9). However, approximately one of the four subunits contains an inactive high-spin Fe (III)-biliverdin complex.
Iron in catalase