Fibronectin-binding peptides. I. Isolation and characterization of two unique fibronectin-binding peptides from gelatin.

Gelatin binds to fibronectin with a high affinity although the fibronectin-binding components have not been located. Fibronectin plays an important role in tumor cell metastasis and gelatin may have a profound effect on the metastatic process. In this study, fractionated acid-washed gelatin was cleaved with trypsin and resultant peptides fractionated by fibronectin-Sepharose affinity chromatography. After further purification using size exclusion HPLC and then reverse-phase HPLC, two unique peptides were obtained and sequenced. The binding affinities of these two peptides to fibronectin were evaluated by an ELISA method developed during this study and compared with the gelatin. Both possessed significantly higher binding affinities to fibronectin than gelatin alone.