Provided herein is a method for inducing formation of a conformationally distinct superfibronectin by contacting plasma fibronectin with BBK32 protein or a BBK32 peptide and the BBK32-induced superfibronectin so formed. Also provided are methods of inhibiting endothelial cell proliferation, of treating pathophysiological conditions associated with endothelial cell proliferation and of inhibiting angiogenesis therein using the BBK32 protein, BBK32 peptide or the BBK32-induced superfibronectin.