Group A streptococci bind human plasmin but not other structurally related proteins

Certain group A streptococci are known to possess a receptor for the human enzyme plasmin. Plasmin is a member of a super gene family that includes other serine proteases and kringle containing proteins. In this study we have examined the interaction of a group A streptococcus with structurally related proteins, including plasmin, glu-plasminogen, tissue plasminogen activator, kallikrein, factor XII, prothrombin, thrombin, trypsin, and urokinase. Our studies indicate that only the key fibrinolytic enzyme, plasmin, demonstrates significant binding activity to the group A streptococcus.