Plasminogen (Pg) is synthesized in the liver and circulates in plasma at a concentration of ~200ug/ml (~2.3uM). Plasminogen is a single-chain glycoprotein of ~88kD that consists of a catalytic domain followed by five kringle structures. Within these kringle structures are four low-affinity lysine binding sites and one high- affinity lysine binding site. It is through these lysine binding sites that plasminogen binds to fibrin and to alpha-2antiplasmin. Native plasminogen (glu-plasminogen) exists in two variants that differ in their extent of glycosylation, and each variant has up to six isoelectric forms with respect to sialic acid content, for a total of 12 molecular forms. Activation of glu-plasminogen by the plasminogen activators urokinase (UPA), or tissue plasminogen activator (tPA) occurs by cleavage after residue Arg560 to produce the two-chain active serine protease plasmin.
In a positive feedback reaction, the plasmin generated cleaves an ~8kD peptide from glu- plasminogen, producing lys77-plasminogen which has a higher affinity for fibrin and when bound is a preferred substrate for plasminogen activators such as urokinase. Additional activators of plasminogen include kallikrein and activated factor XII. The primary inhibitor of plasmin in plasma is alpha-2antiplasmin. Other physiological inhibitors of plasmin include alpha-2macroglobulin and antithrombin.
Materials Supplied:Antibodies for 5x96 well plates
Storage and Stability:Store components at 4°C. Stable for 6 months. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.
