Protein pa of an enzyme is called

The protein without the prosthetic group is called the apoenzyme: it is catalytically inactive. Many enzymes require an additional small molecule, known as a cofactor to aid with catalytic activity. A cofactor is a non-protein molecule that carries out chemical reactions that cannot be performed by the standard 20 amino acids. Cofactors can be either inorganic molecules (metals) or small organic molecules (coenzymes).Cofactors, mostly metal ions or coenzyme, are inorganic and organic chemicals that function in reactions of enzymes. Coenzymes are organic molecules that are nonproteins and mostly derivatives of vitamins soluble in water by phosphorylation; they bind apoenzyme protein molecule to produce active holoenzyme.Apoenzyme- An enzyme that requires a cofactor but does not have one bound. An apoenzyme is an inactive enzyme, activation of the enzyme occurs upon binding of an organic or inorganic cofactor.Ref: Reginald H.Garrett and Charles M. Grisham, page no: 385