Statement A: Non-protein constituents called cofactors are bound to the enzyme to make the enzyme catalytically active.
Statement B: Catalytic activity is lost when the co-factor is removed from the enzyme.

Non-protein constituents called cofactors are bound to the enzyme to make the enzyme catalytically active. In these instances, the protein portion of the enzymes is called the apoenzyme. Three kinds of cofactors may be identified: prosthetic groups, co-enzymes and metal ions.
Catalytic activity is lost when the co-factor is removed from the enzyme which testifies that they play a crucial role in the catalytic activity of the enzyme.