摘要

Purified from Bauhinia rufa seeds, BrTI is a Kunitz proteinase inhibitor that contains the RGD sequence. BrTI inhibits trypsin (K_iapp 2.9 nM) and human plasma kallikrein (K_iapp 14.0 nM) but not other related enzymes. The synthetic peptide YLEPVARGDGGLA-NH₂ (70 μM) inhibited the adhesion to fibronectin of B16F10 (high-metastatic B16 murine mouse melanoma cell line) and of Tm5 (murine melanoma cell lines derived from a non-tumorigenic lineage of pigmented murine melanocytes, melan-a). YLEPVARGEGGLA-NH₂ in which Asp⁹ was changed into Glu does not affect the cell attachment. Moreover, this peptide was functional only when the sequence present in the native protein was preserved, since YLIPVARGDGGLA-NH₂ in which Glu³ was changed into Ile does not interfere with B16F10 and was less effective on Tm5 cell line adhesion. Neither YLEPVARGDGGLA-NH₂, YLIPVARGDGGLA-NH₂ or YLEPVARGEGGLA-NH₂ inhibit the interaction of RAEC (endothelial cell line from rabbit aorta) with fibronectin.