How are prosthetic groups different from co-factors?

 

 
Prosthetic groups are organic compounds that aretightly bound to the apoenzyme, (an enzyme without cofaetor) by covalent or non-covalent forces, e.g., in peroxidase and catalase, which catalyse the breakdown of hydrogen peroxide to water and oxygen, haeme is the prosthetic group and it is a part of the active site of the enzyme.
 
 
Co-factor is small, heat stable and non-protein part of conjugate enzyme. It may be inorganic or organic in nature.
Co-factors when loosely bound to a enzyme is called coenzyme and when tightly bound to apoenzyme is called prosthetic group.