Question

Co-factor and prosthetic groups are __________ compounds, ________ bound to apoenzyme.

• A. organic, transiently
• B. inorganic, tightly
• C. organic, tightly
• D. inorganic, transiently

Answer 1

Answer: (C)

Enzymes are proteinaceous in nature. Some Enzymes also contain non-protein part known as Co-factors. These factors are attached to the Enzymes to enhanced their catalytic activity. The protein part of Enzyme is known as Apoenzyme. Hence Apoenzyme (Protein part) + Co-factors (Non protein part) = Holoenzyme (Whole Enzyme). As the co-factors are bound to enzymes, the removal of these factors affects the overall activity of Enzymes too. These co-factors can be organic or inorganic. Organic cofactors if tightly bound are known as Prosthetic groups and if loosely bound are termed as Co-enzymes. The inorganic co-factors are metal ions. Example of inorganic co-factor is Zinc which is a co-factor of enzyme Carboxypeptidase.