Which peptide bonds does streptokinase cleave to activate plasminogen?

Streptokinase functions by converting plasminogen into plasmin, an enzyme responsible for breaking down fibrin in blood clots. The activation process involves the cleavage of specific peptide bonds within the plasminogen molecule. The bond between Arg561 and Val562 is crucial because it initiates a conformational change that effectively transforms plasminogen into its active form, plasmin.

This specificity for the Arg561 and Val562 bond underscores the importance of individual amino acid sequences in regulating protein activity and interaction. Thus, when streptokinase binds to plasminogen, it facilitates cleavage at this particular site, allowing for effective conversion and subsequent clot lysis. Understanding this mechanism is essential for comprehending the pharmacological action of streptokinase in clinical settings aimed at treating thrombotic conditions.