Vitronectin is a secreted glycoprotein which is synthesized in the liver. It circulates primarily in monomeric form, but can undergo conformational change to a structure that forms disulfide linked multimers. The multimeric Vitronectin can efficiently bind to and incorporate into the extracellular matrix. Within the matrix, Vitronectin can support cell adhesion through binding to various integrins and other proteoglycans. Additionally, recombinant vitronectin can function as a chemically defined matrix component in human embryonic stem cell renewal media. Recombinant human Vitronectin is a 459 amino acid single chain monomeric protein, which migrates at an apparent molecular weight of 75 kDa by SDS-PAGE under reducing conditions.