The protein part of an enzyme which requires a coenzyme for activity, and is therefore inactive if the coenzyme is absent.
The protein part of a holoenzyme. Many (but not all) enzymes are composed of functional “pieces.” For example, a protein piece (chain) and another piece that is an organic and/or inorganic molecule. This other piece is known as a cofactor and it may be removed from the enzyme under certain conditions. When this is done, the resulting inactive enzyme is known as an apoenzyme. The inactive apoenzyme becomes functionally active again if it is allowed to reombine with its cofactor.
Any protein that forms an active enzyme system by combination with a coenzyme and that determine the specificity of this system for any one substrate.
The inactive part or “backbone” of an enzyme protein.
Protein that combines with a coenzyme (non-protein, e.g., some vitamins) to form an active enzyme.
The protein portion of an enzyme.