A peptidomimetic compound represented by the general formula Ia or a salt thereof, wherein R 1 and R 4 are independently selected from the group consisting of H, an alkyl group, alkenyl group, alkynyl group, alkoxy group, aryl group, heteroaryl group, cyano group, nitro group, phosphate group and sulfoxyl group; R 2 and R 3 are independently selected from the group consisting of an alkyl group, alkenyl group, alkynyl group, alkoxy group, aryl group, heteroaryl group, cyano group, nitro group, phosphate group and sulfoxyl group; X represents -(CH x Fy) z -, wherein x+y = 2, x = 0, 1 or 2, y = 0, 1 or 2 and z = 2 to 4; Y 1 and Y 2 are independently selected from S, SO 2 N, N-alkyl, or O; P 1 and P 3 each independently represents a single amino acid residue or a peptide sequence of 2 or more amino acid residues; P 2 is absent or represents a single amino acid residue or a peptide sequence of 2 or more amino acid residues; Q is C or N; R 5 is selected from H, an alkyl group, heteroalkyl group, alkenyl group, heteroalkenyl group, alkynyl group or a heteroalkynyl group, and is bound to Q or may form a ring together with Q and N, or R 5 is absent; R 6 is selected from H, an alkyl group, heteroalkyl group, alkenyl group, heteroalkenyl group, alkynyl group, heteroalkynyl group, alkoxy group, aryl group, and heteroaryl group, or is absent; and R 7 is selected from H, a natural amino acid side chain, an alkyl group, heteroalkyl group, alkenyl group, heteroalkenyl group, alkynyl group, heteroalkynyl group, alkoxy group, aryl group or a heteroaryl group; with the proviso that when P 2 is absent, P 1 and P 3 are not bonded to each other; with the proviso that when Q is N, R 5 is absent, and with the proviso that when R 5 forms a ring together with Q and N, R 6 is absent. R 1 and R 4 are independently selected from the group consisting of H, an alkyl group, alkenyl group, alkynyl group, alkoxy group, aryl group, heteroaryl group, cyano group, nitro group, phosphate group and sulfoxyl group; R 2 and R 3 are independently selected from the group consisting of an alkyl group, alkenyl group, alkynyl group, alkoxy group, aryl group, heteroaryl group, cyano group, nitro group, phosphate group and sulfoxyl group; X represents -(CH x Fy) z -, wherein x+y = 2, x = 0, 1 or 2, y = 0, 1 or 2 and z = 2 to 4; Y 1 and Y 2 are independently selected from S, SO 2 N, N-alkyl, or O; P 1 and P 3 each independently represents a single amino acid residue or a peptide sequence of 2 or more amino acid residues; P 2 is absent or represents a single amino acid residue or a peptide sequence of 2 or more amino acid residues; Q is C or N; R 5 is selected from H, an alkyl group, heteroalkyl group, alkenyl group, heteroalkenyl group, alkynyl group or a heteroalkynyl group, and is bound to Q or may form a ring together with Q and N, or R 5 is absent; R 6 is selected from H, an alkyl group, heteroalkyl group, alkenyl group, heteroalkenyl group, alkynyl group, heteroalkynyl group, alkoxy group, aryl group, and heteroaryl group, or is absent; and R 7 is selected from H, a natural amino acid side chain, an alkyl group, heteroalkyl group, alkenyl group, heteroalkenyl group, alkynyl group, heteroalkynyl group, alkoxy group, aryl group or a heteroaryl group;