the term 34 amino acids surrounding the arg gly asp sequence 34 refers both to residues adjacent to the arg gly asp sequence as well as to residues separated from the arg gly asp sequence by intervening residues as used herein references to 34 arg gly asp containing peptides 34 are intended to refer to peptides having one or more arg gly asp containing binding sites which may function as binding sites for a receptor of the 34 arg gly asp family of receptors 34 i e those recognizing and binding to the arg gly asp sequence while the arg gly asp sequence has bean found to necessarily be invariant in order to retain the binding activity the composition of the remaining peptide as well as any other chemical moiety present in conjunction with the peptide may vary without necessarily affecting the activity of the binding site where specific chemical structures or sequences beyond the arg gly asp sequence are presented it is intended that various modifications which do not destroy the function of the binding site are to be encompassed without departing from the definition of the peptide as used herein the term 34 bridge 34 refers to a chemical bond between two amino acids in a peptide other than the amide bond by which the backbone of the peptide is formed as used herein the term 34 peptide bond 34 or 34 peptide linkage 34 refers to an amide linkage between a carboxyl group of one amino acid and the u03b1 amino group of another amino acid the abbreviations for amino acids are used herein are given in the following table.