Let me share with you a comparison between Apoenzyme and Holoenzyme.
| Aspect | Apoenzyme | Holoenzyme |
| Introduction | Inactive enzyme without its cofactor. | Active enzyme with its cofactor. |
| Need of cofactor | Requires a cofactor for activation. | Contains the necessary cofactor for its activity. |
| Activity | Inactive or has significantly reduced activity. | Active and capable of catalyzing reactions. |
| Composition | Protein component only. | Protein component (apoprotein) + Cofactor (coenzyme or metal ion) = Holoenzyme. |
| Activation | Becomes active upon binding with a cofactor. | Constitutively active due to cofactor presence. |
| Role | Serves as a precursor to the active enzyme. | Represents the fully functional, catalytically active form of the enzyme. |
| Regulation | Regulation often involves the addition of cofactors to convert apoenzyme to holoenzyme. | Regulation may involve changes in cofactor availability or modulation of holoenzyme activity. |
| Examples | · Apo-cytochrome c
· Apo-ribonuclease |
· Holo-cytochrome c (with heme)
· Holo-ribonuclease (with zinc ion) |