title: Poly-lysines as modifiers of one- and two-chain tissue-type plasminogen activator activity.
abstract: Poly-L-lysine and certain mixed polymers of L-lysine and other amino acids modify the activity of one- and two-chain tissue-type plasminogen activator (t-PA) towards its substrates. In particular the rate of plasminogen activation in the presence of optimal poly-L-lysine concentrations, is increased by approximately 100-fold. In contrast, activity towards a small synthetic substrate is inhibited by 85%. These effects are observed with both the one- and two-chain forms of t-PA. The use of poly-L-lysines in a coupled assay system optimised for t-PA and plasmin activities allows the reproducible assay of t-PA at the 10(-12) to 10(-13) molar level.
mesh_terms: D004789:Enzyme Activation; D006801:Humans; D008722:Methods; D008970:Molecular Weight; D010958:Plasminogen / Q000378:metabolism; D011107:Polylysine / Q000494:pharmacology*; D011487:Protein Conformation; D013379:Substrate Specificity; D010959:Tissue Plasminogen Activator / Q000378:metabolism*
chemical_list: D011107:Polylysine; D010958:Plasminogen; D010959:Tissue Plasminogen Activator