CHIMERIC TRUNCATED TISSUE PLASMINOGEN ACTIVATOR (t-PA) RESIATANT TO PLASMINOGEN ACTIVATOR INHIBITOR-1 AND IMPROVED BIOCHEMICAL PROPERTIES

摘要

The present invention discloses a thrombolytic therapy for acute myocardial infarction by t-PA. A chimeric truncated form of t-PA is designed and expressed in Pichia pastoris. The new variant t-PA comprises of a finger domain of Desmoteplase, an epidermal growth factor (EGF) domain, a kringle 1 domain, a kringle 2 domain in which the lysine binging site is deleted, and a protease domain where the four amino acids lysine 296, arginine 298, arginine 299, and arginine 304 are substituted by aspartic acid. The chimeric t-PA shows has increased activity of 14 fold in presence of fibrin. The t-PA shows 10-fold increased potency than commercially available full length t-PA (Actylase®) and provides 1.2 fold greater affinity to fibrin. Further a residual activity of only 68% is observed after incubation of Actylase® with PAI-1 and 91% residual activity for t-PA. The t-PA variant is acceptable plasminogen activator with enhanced biochemical properties.

主权项

1. A chimeric truncated tissue plasminogen activator CT t-PA comprising:
a native human t-PA with a F domain, an EGF domain, a K1 domain, a K2 domain and a protease (P) domain; wherein the F domain of native human t-PA is replaced by F domain of vampire bat plasminogen activator, and wherein 24 amino acids (LBS) of the K2 domain are deleted at a position of 202-225, and wherein the amino acids K296, R298, 8299 and R304 in the P domain are replaced by four aspartic acids (DDDD).