Human tissue plasminogen activator, purified, glycosylated, 355 residues purified from CHO cells. Retavase is considered a “third-generation” thrombolytic agent, genetically engineered to retain and delete certain portions of human tPA. Retavase is a deletion mutein of human tPA formed by deleting various amino acids present in endogenous human tPA. Retavase contains 355 of the 527 amino acids of native human tPA (amino acids 1-3 and 176-527), and retains the activity-related kringle-2 and serine protease domains of human tPA. Three domains are deleted from retavase – kringle-1, finger, and epidermal growth factor (EGF).