Characteristics of ß-endorphin interaction with complement S protein/vitronectin in vitro

Vitronectin is a glycoprotein, which plays a functional role in the complement system as well as in the coagulation system; moreover, as an «adhesion molecule», it is able to promote surface attachment and spreading of cells in culture (1). Recently it has been shown to exhibit specific binding sites for human β H -endorphin upon interaction with heparin or surfaces. The C-terminal residues of the β H -endorphin amino acid sequence, -GLY-GLU, proved to be essential for β H -endorphin binding, but the affinities of C-terminal β H -endorphin fragments increased with B-endorpin sequence elongation in N-terminal direction (2)