NEETChemistryBiomolecules
Identify the correct statement regarding the cofactor present in the enzyme peroxidase.
Options
- AIt is haem, which acts as a co-enzyme and binds transiently to the apoenzyme.
- BIt is haem, which is a prosthetic group and is tightly bound to the apoenzyme.
- CIt is zinc, which forms coordination bonds with side chains at the active site.
- DIt is haem, which is an inorganic metal ion that binds tightly to the apoenzyme.
Correct answer
B. It is haem, which is a prosthetic group and is tightly bound to the apoenzyme.
Step-by-step solution
In the enzymes peroxidase and catalase, which catalyse the breakdown of hydrogen peroxide to water and oxygen, haem is the cofactor. Haem is a prosthetic group. According to NCERT, prosthetic groups are organic compounds that are distinguished from other cofactors in that they are tightly bound to the apoenzyme. Zinc is a metal ion cofactor for carboxypeptidase, not peroxidase. Co-enzymes associate only transiently, whereas haem in peroxidase is tightly bound. Haem is an organic compound (porphyrin derivative), not