Question

Matrix metalloproteinases are -

• A. Cathepsin
• B. Zn metalloproteinases
• C. Cu metalloproteinases
• D. Cd metalloproteinases

Hint:

Metallo- in MMP refers to a zinc ion in the active site.

Answer 1

The Correct Option is B

Step 1: Identify the enzyme family. Matrix metalloproteinases (MMPs) degrade collagen and other extracellular matrix (ECM) components during tissue remodeling and scar maturation. The outcome of repair depends on the balance between synthesis and degradation of ECM proteins.

Step 2: Why zinc. They are called metalloproteinases because they require a metal ion in their active site for catalytic activity, and that ion is zinc. So MMPs are zinc-dependent enzymes, making Zn metalloproteinases the correct answer.

Step 3: Members. The family includes interstitial collagenases (MMP-1, -2, -3) that cleave fibrillar collagen, gelatinases (MMP-2 and MMP-9) that degrade amorphous collagen and fibronectin, and stromelysins (MMP-3, -10, -11) that degrade proteoglycans, laminin, fibronectin and amorphous collagen.

Step 4: Why the others are wrong. Cathepsins are a separate group of lysosomal proteases (often cysteine or aspartic proteases), not MMPs. Copper (Cu) and cadmium (Cd) are not the catalytic metal of MMPs. Hence Zn metalloproteinases is correct.