Vitronectin is a large glycoprotein found in blood and the extracellular matrix (ECM). The gene for Vitronectin encodes a 19 amino acid (aa) signal peptide and a 459 aa protein. The amino terminal 130 aas of Vitronectin contains multiple binding sites for a variety of structures. Included is a site for binding to plasminogen activator inhibitor 1 (PAI1) and urokinase receptor, an (RGD) sequence that binds alphavbeta3, alphavbeta5, alphavbeta1, alphaIIbbeta3, alphavbeta6, and alphavbeta8 integrins, a stretch of acidic amino acids that includes two sulfated tyrosine residues that bind thrombinantithrombin III complexes, and a collagen binding site. The major part of the Vitronectin molecule (aa 132 459) contains six hemopexin repeats (Hemopexin domains are associated with enzyme and protein binding). The carboxylterminal end of Vitronectin has multiple sites and fucntions. It contains a stretch of basic amino acids that binds the acidic amino acids of the amino terminal region, thereby stabilizing Vitronectin s three dimensional structure. The carboxylterminal end also contains a plaminogen binding site, a heparin binding site that binds complement factor C7, C8 or C9, a glycosaminoglycan binding site, and a second PAI1 binding site (aa 348 370). Vitronectin also contains an endogenous cleavage site, plus cleavage sites for elastase, thrombin and plasmin. Vitronectin has also been shown to bind IGF2 and TGFbeta. The apparent molecular weight of human Vitronectin is 75kD, with ~30% of its molecular mass being attributed to glycosylation at 3 different sites. In blood and plasma, Vitronectin is found predominantly as a single chain monomer. It can also be found as a dimer after endogenous cleavage. The dimer is composed of a 65kD and 10kD component held together by a disulfide bond. Binding of thrombinantithrombin II complex or complement leads to an unfolding of Vitronectin. Unfolding of Vitronectin generates disulfidelinked multimers that are found in platelet secretions and extracellular matrix. Vitronectin is produced at high levels by the liver and many tumors. As might be expected by its structure, Vitronectin is involved in a number of biological activities including cell adhesion, cell spreading and migration, cell proliferation, extracellular anchoring, fibrinolysis, hemostasis, and complement mediated immune defense. N-terminal Sequence Analysis: DQESCKGRCT Source: Human plasma derived. The human plasma used for the isolation of this product were certified by the supplier to be HIV1 and HBsAg negative at the time of shipment. Human blood products should always be treated in accordance with universal handling precautions. Molecular Weight: 78kD Activity: Measured by the ability of the immobilized protein to support the adhesion of DU145 human prostate carcinoma cells or B16-F1 mouse melanoma cells. When 5x10e4 cells/well are added to Vitronectin coated plates (5ug/mL with 100ul/well), approximately >55% will adhere after 30 minutes at 37C. Optimal concentration depends on cell type as well as the application or research objectives. Storage and Stability: Lyophilized and reconstituted products are stable 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.
