Both are thrombolyltic drugs. Streptokinase binds to the active
complex. It promotes the cleavage of the Arg/Val bond of
plasminogen leading to the formation of plasmin. The plasmin then
breaks down the matrix of the thrombus.
A tissue plasminogen activator is alteplase. It binds to
fibrin-rich clots and cleaves the Arg/Val bond of plasminogen to
produce plasmin. The plasmin then breaks down the matrix of the
thrombus.