Gelatin Sepharose 4B is bovine gelatin coupled to Sepharose 4B by the cyanogen bromide method. Gelatin binds specifically to fibronectin, which is a high molecular weight glycoprotein found on the surfaces of many cell types and present in many extracellular fluids including plasma. Gelatin Sepharose 4B has been designed for the purification or removal of fibronectin.