Advanced Dental Admission Test (ADAT)

Matrix metalloproteinases (MMPs) are proteolytically activated by which enzyme?

1. Thrombin

2. Fibrinogen

3. Collagenase

4. Plasmin

The correct answer is: Plasmin

Matrix metalloproteinases (MMPs) are a group of enzymes responsible for the degradation of various components of the extracellular matrix, playing a crucial role in tissue remodeling and repair. The activation of MMPs occurs through proteolytic cleavage, a process in which an enzyme cuts specific peptide bonds in a precursor form of MMPs, known as proMMPs. Plasmin is the enzyme recognized for its role in fibrinolysis, the breakdown of fibrin in blood clots. It activates proMMPs by cleaving them, allowing the MMPs to enter an active form capable of degrading extracellular matrix components. This activation process is particularly significant during wound healing and tissue remodeling where the degradation of extracellular matrix is necessary for cell migration and new tissue formation. While other choices refer to substances or enzymes involved in coagulation or matrix remodeling, they do not directly activate MMPs in the same way as plasmin. Fibrinogen is a precursor protein involved in clot formation, thrombin is an enzyme in the clotting cascade, and collagenase refers to a specific type of MMP that breaks down collagen but is itself an MMP rather than an enzyme that activates MMPs. Thus, the relationship between M