Certain group A streptococci demonstrate surface receptors that bind selectively to the key fibrinolytic enzyme, plasmin. These bacteria show no reactivity with the zymogen protein plasminogen or with other serine class proteases, such as trypsin or urokinase. Bacterium-bound plasmin retains its ability to cleave synthetic substrates and its ability to hydrolyze a fibrin clot. The bacterium-bound plasmin is not effectively regulated by its physiological regulator, alpha 2-plasmin inhibitor. This study is the first report of a bacterium-associated receptor for plasmin.