The correct answer is option 'B': carboxy peptidase catalyzes the hydrolysis of proteins and requires zinc (Zn) as a cofactor.

Function of Carboxy Peptidase:
Carboxy peptidase is an enzyme that belongs to the class of hydrolases. It acts on the carboxyl terminus of peptides and catalyzes their hydrolysis. Hydrolysis refers to the cleavage of peptide bonds in proteins by the addition of a water molecule. Carboxy peptidase specifically acts on the carboxyl (C-terminal) end of peptide chains, removing one amino acid at a time. This process is essential for the breakdown of proteins into smaller peptides and amino acids, which can then be utilized by the body for various metabolic processes.

Metal Associated with Carboxy Peptidase:
Carboxy peptidase requires a metal ion as a cofactor to catalyze its enzymatic activity. In the case of carboxy peptidase, the metal ion associated with its function is zinc (Zn). Zinc ions play a crucial role in stabilizing the enzyme-substrate complex and facilitating the hydrolysis reaction. The zinc ion acts as a Lewis acid, coordinating with the substrate and promoting the nucleophilic attack of water on the peptide bond, resulting in the hydrolysis of the bond. The coordination of zinc with the enzyme's active site helps in orienting the substrate and facilitating the catalytic reaction.

Importance of Zinc in Enzyme Function:
Zinc is a transition metal that is essential for the proper functioning of numerous enzymes in the human body. It plays a vital role in various biological processes, including DNA synthesis, protein synthesis, and enzymatic catalysis. Zinc acts as a cofactor for many enzymes, including carboxy peptidase, by providing a stable coordination site for the substrate and assisting in the catalytic reaction. Without the presence of zinc, the enzymatic activity of carboxy peptidase would be greatly diminished or completely abolished.

In summary, carboxy peptidase is an enzyme that catalyzes the hydrolysis of proteins, specifically acting on the carboxyl terminus of peptides. It requires zinc as a cofactor to facilitate its enzymatic activity. The coordination of zinc with the enzyme's active site helps in orienting the substrate and promoting the hydrolysis reaction.