ABSTRACT
This chapter presents procedures for the isolation of plasma fibronectin and cellular fibronectin. It provides compare published methods in general terms, then a detailed, recommended protocol for purification of each form of fibronectin. Plasma fibronectin is also known as "cold insoluble globulin" or " α-2 opsonic glycoprotein." Amniotic cells produce a third type of fibronectin that is unusual in its high degree of glycosylation. Outdated human plasma can be obtained from blood banks, anticoagulated by either citrate or ethylenediaminetetraacetic acid (EDTA). The supernatant plasma is applied to the precolumn at room temperature, and the flow-through material is applied as it is collected to the gelatin affinity column. Cellular fibronectin poses unusual problems in purification due to its insolubility at neutral pH after purification. The use of tertiary cultures substantially reduces contamination with nonfibrob-lastic cells and also appears to decrease the amount of procollagen production without decreasing quantities of fibronectin synthesized.
