The urokinase-type plasminogen activator (uPA) is one of two activators that converts the extracellular zymogen plasminogen to plasmin, a serine protease that is involved in a variety of normal and pathological processes that require cell migration and/or tissue destruction. uPA is synthesized and released from cells as a single-chain (sc) pro-enzyme with limited enzymatic activity and is converted to an active two-chain (tc) disulfide-linked active enzyme by plasmin and other specific proteinases. Both the scuPA and tcuPA bind with high-affinity to the cell surface via the glycosyl phosphatidylinositol-linked receptor uPAR which serves to localize the uPA proteolytic activity. The enzymatic activity of scuPA has also been shown to be enhanced by binding to uPAR. Independent of their proteolytic activity, the uPA/uPAR interaction also initiates signal transduction responses resulting in activation of protein tyrosine kinases, gene expression, cell adhesion, and chemotaxis. uPAR can interact with integrins to suppress normal integrin adhesive function and promote adhesion to vitronectin through a high affinity vitronectin binding site on uPAR. uPAR cDNA encodes a 335 amino acid residue precursor protein with a 22 aa residue signal peptide, five potential N-linked glycosylation sites and a C-terminal GPI-anchor site. An alternate spliced variant of uPAR encoding a secreted soluble form of uPAR also exists. Human and mouse uPAR share approximately 60% amino acid sequence identity and the receptor-ligand interaction is strictly species-specific. NS0-derived, recombinant human uPAR, Lue23-Arg303, with a C-term 6-His tag Swiss/UniProt Accession: Q03405 Applications: Suitable for use in ELISA. Other applications have not been tested. Recommended Dilutions: Optimal dilutions to be determined by the researcher. Biological Activity: Measured by its binding ability in a functional ELISA. Immobilized rhUPAR at 5ug/ml (100ul/well) can bind rhuPA with a linear range of 0.3-20ng/ml. Molecular Mass: The 287aa residue recombinant mature uPAR (generated after removal of a 22aa residue signal peptide) has a predicted molecular mass of approximately 31kD. As a result of heterogeneous glycosylation, the recombinant uPAR migrates as a broad band of 40-55kD in SDS-PAGE under reducing conditions. Storage and Stability: Lyophilized and reconstituted products are stable for 6 months after receipt at -20C. Reconstitute with sterile PBS. Aliquot to avoid repeated freezing and thawing. Store at -20C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.
