A holoenzyme is best described as

A holoenzyme is best described as

• A. Not bound to cofactors
• B. Inactive enzyme
• C. Active enzyme bound to cofactors
• D. Enzyme lacking a prosthetic group

Answer: (C)

A holoenzyme is the active form of an enzyme that includes its non-protein helpers, called cofactors, bound to the protein part. When the protein portion is alone, it’s called an apoenzyme and is usually inactive because the cofactor is needed to complete the active site and enable catalysis. Prosthetic groups are cofactors that stay tightly bound, forming the holoenzyme. Because the bound cofactor properly supports substrate binding and the chemical steps of the reaction, the holoenzyme is capable of catalyzing the reaction, whereas the other states described lack that complete, active setup.

A holoenzyme is the active form of an enzyme that includes its non-protein helpers, called cofactors, bound to the protein part. When the protein portion is alone, it’s called an apoenzyme and is usually inactive because the cofactor is needed to complete the active site and enable catalysis. Prosthetic groups are cofactors that stay tightly bound, forming the holoenzyme. Because the bound cofactor properly supports substrate binding and the chemical steps of the reaction, the holoenzyme is capable of catalyzing the reaction, whereas the other states described lack that complete, active setup.