Recombinant Human t-Plasminogen Activator (t-PA) (carrier-free)
Description
Plasminogen activator, also known as PA, is a serine protease which converts inactive proenzyme plasminogen to active protease plasmin. PA has been classified in two types: urokinase–like activator and tissues plasminogen activator (t-PA). The principal plasminogen activator is t-PA, which is synthesized mainly by endothelial cells, and is secreted locally after stimulation of the endothelium by histamine, adrenalin, thrombin, FXa, and hypoxia. T-PA is secreted as a protein of 527 amino acids. The molecule possesses four highly conserved structural domains: the amino-terminal fibronectin type-1 domain, an epidermal growth factor-like domain, two kringle domains, and the carboxi-terminal which contains the serine protease catalytic domain. The concentration of t-PA in serum is approximately 0.1 nM under normal physiological conditions, and a big portion of t-PA in serum is associated to plasminogen-activator inhibitor type 1 (PAI-1). The inhibitor interacts with positively charged amino acids near the catalytic site of t-PA. The t-PA-PAI-1 inactive heterodimeric complexes are cleared from the circulation by the liver, while the complexes are internalized by the low density lipoprotein receptor-related protein (LRP-1). T-PA plays an important role in the removal of intravascular fibrin deposits, and it has been used in the treatment of acute ischemic stroke.