Expression of MMP2 by human platelets.

Human washed platelets were resuspended in Tyrode's buffer and were divided into 2 groups corresponding to resting and collagen- (1 μg/mL) aggregated platelets. Supernatants from resting and activated platelets as well as the platelet pellet solubilized in the sample buffer (lane 3) were studied by gelatin zymography in a 7.5% acrylamide gel containing 1-mg/mL gelatin under nonreduced conditions. Gelatinolytic activity at 68 kd and at 62 to 59 kd was visualized, indicating the presence of MMP2 in proform in resting platelets (lane 1) and in proform and activated forms in activated platelets (lane 2).