Identification of key gene products required for acquisition of plasmin-like enzymatic activity by group A streptococci.

Group A streptococci incubated in human plasma can acquire a plasmin-like enzymatic activity. This process involves at least two bacterial proteins and two human protein cofactors. In this study, the key bacterial proteins were identified by using a series of isogenic mutants of group A isolate, CS101. These studies confirm a key role for the secreted plasminogen activator, streptokinase, and identify the major surface fibrinogen-binding protein as the product of the mrp gene. The requirement for human fibrinogen and plasminogen as key cofactors was also confirmed.