Interaction of human plasma fibronectin with α-elastin

Because there are contradictory reports about the interaction of plasma fibronectin with elastin, we investigated the interaction in vitro. When human plasma was applied to an alpha-elastin-Sepharose column at 4 degrees C, the column-binding fraction contained fibronectin. When isolated plasma fibronectin was applied to the same column at 4 degrees C, most of the fibronectin bound to the column and was eluted with 1 M KBr. However, the binding affinity of plasma fibronectin to the alpha-elastin-Sepharose column was much weaker at 25 degrees C than at 4 degrees C. The elastin-plasma fibronectin interaction was further confirmed by demonstrating the binding of alpha-elastin to fibronectin on polyvinylidene difluoride membranes using an alpha-elastin specific antibody. The elevation of the surface hydrophobicity of plasma fibronectin at 4 degrees C was observed by hydrophobic chromatography, using alkyl-Sepharose columns. It seems that the binding of plasma fibronectin to alpha-elastin involves hydrophobic interaction, which is affected by temperature and possibly by other factors.