not precipitate this indicates that floating of the 140 kd protein occurs only in the presence of phospholipid vesicles and is not due to the presence of residual detergent bound to the protein these results indicate that the 140 kd protein can become inserted into a lipid bilayer as depicted in fig5 liposomes containing the 140 kd protein bound to fibronectin coated microtiter wells in a dose dependent manner similar to the attachment of cells to fibronectin in contrast no significant binding to another adhesive glycoprotein laminin engvall et al 1983 was observed in further control experiments it was found that neither liposomes without incorporated protein nor liposomes prepared from a crude octylglucoside extract of cells adhered to fibronectin coated wells in addition the binding was specifically inhibited by the cell attachment peptide grgdsp fig6 this peptide at a concentration of 1 mg ml inhibited the binding of liposomes by approximately 50 while inactive variants grgesp and gradsp alanine replacing glycine in the latter peptide were without any effect at the same concentration increasing the concentration of the peptides to 4 mg ml resulted in a higher degree of inhibition but at this concentration some apparent nonspecific inhibition was observed chromatography on wga sepharose or cona.