Plasminogen activator, tissue (PLAT, synonyms: TPA, T-PA) is a tissue-type plasminogen activator, a secreted serine protease which converts the proenzyme plasminogen to plasmin, a fibrinolytic enzyme. Tissue-type plasminogen activator is synthesized as a single chain which is cleaved by plasmin to a two chain disulfide linked protein (33 kDa and 32 kDa). PLAT enzyme plays a role in cell migration and tissue remodeling. Increased enzymatic activity causes hyperfibrinolysis, which manifests as excessive bleeding; decreased activity leads to hypofibrinolysis which can result in thrombosis or embolism. tPA has 4 isoforms produced by alternative splicing with the MW of 63 kDa, 33 kDa, 57 kDa and 44 kDa.
