Introduction Tissue-type plasminogen activator (tPA) is a serine protease that converts the zymogen plasminogen into the active serine protease plasmin, the primary enzyme responsible for the removal of fibrin deposits (1). tPA is a 68 kDa glycoprotein that is synthesized by endothelial cells in normal blood vessels, and displays relatively high affinity for fibrin, suggesting that it functions predominately in physiological thrombolysis in vivo (2). A high level of tPA is a good prognostic marker for breast cancer (3 - 4). tPA may minimize the formation of metastasis by preventing tumor cell adherence at sites of trauma (5). On the other hand, gastrointestinal cancer is accompanied by a decrease in tPA (6).
Principle of the Assay The AssayMax Human Tissue-Type Plasminogen Activator ELISA kit is designed for detection of human tPA in plasma, serum, urine, saliva, milk, cell culture supernatants, and tissue extract. This assay employs a quantitative sandwich enzyme immunoassay technique that measures tPA in less than 4 hours. A polyclonal antibody specific for tPA has been pre-coated onto a microplate. Human tPA in standards and samples is sandwiched by the immobilized antibody and a biotinylated antibody specific for tPA, which is recognized by a streptavidin-peroxidase conjugate. All unbound material is then washed away and a peroxidase enzyme substrate is added. The color development is stopped and the intensity of the color is measured.