Interaction of the fibronectin COOH-terminal Fib-2 regions with fibrin: Further characterization and localization of the Fib-2-binding sites

A dimeric 140 kDa [(Fib-2).sub.2] fragment containing both Fib-2 regions are prepared by limited proteolysis in order to clarify the role of another pair of fibrin-binding regions, Fib-2, located at the disulfide-linked COOH-terminal ends of fibronectin. Experiments revealed about 30% inhibition of the Fib-2 mediated binding by increasing concentrations of Fib-1 fragment.