Bioactive peptides

A peptide as claimed in any one of the preceding claims wherein the non-genetic bulky and lipophilic amino acid is a modified aromatic residue.

A peptide as claimed in any one of the preceding claims which is amphipathic in nature.

A cytotoxic 7 to 25 mer peptide with three or more cationic residues, whose N-terminus is modified by a cyclic group comprising at least 5 non-hydrogen atoms, as well as esters, amides, salts and cyclic derivatives thereof.

A cytotoxic 7 to 25 mer peptide with three or more cationic residues, whose C-terminus is modified by a group comprising at least 4 non-hydrogen atoms, as well as salts and cyclic derivatives thereof.

A method of enhancing the cytotoxicity or selectivity of a 7 to 25 mer peptide with three or more cationic residues by incorporating therein a non-genetic bulky and lipophilic amino acid.

A method of preparing a peptide having enhanced cytotoxic activity and/or improved selectivity for certain cell types which comprises incorporating a non-genetic bulky and lipophilic amino acid into a 7 to 25 mer peptide with three or more cationic residues.

A method of preparing tryptophan residues substituted at the 2-position of the indole ring which comprises transferring the group with which the tryptophan will be substituted from a guanidyl containing group to an N-protected tryptophan.