Polypeptides KXK and Their Use

Polypeptide and derivatives thereof, peptide analogs and derivatives thereof, as well as pharmaceutically acceptable salts of these compounds, having the general formula (I):

• A-(Xaa)n-Lys-X-Lys-B wherein:
• i) A=—NH2, NH3+, NH-D, D is an Acyl group being biotin or an alkyl chain from 2 to 22 carbons, linear, or branched or cyclic, substituted or unsubstituted, saturated or unsaturated, hydroxylated or non-hydroxylated, sulfurated or non-sulfurated,
• ii) B═H, O−, OR1 or NR2R3 and R1, R2 and R3 independently either:
• a hydrogen atom, or an alkyl chain of from 1 to 24 carbons, linear, branched or cyclic, substituted or unsubstituted, saturated or unsaturated, hydroxylated or non-hydroxylated, sulfurated or non-sulfurated,
• iii) (Xaa)n is an amino acid chain and (Xaa) is any amino acid natural or non natural, excluding arginine and lysine,
• iv) “n” is between 0 and 3,
• v) X being
• either a chain of two any amino acids (Xaa1Xaa2) which may be the same or different excluding arginine, lysine and excluding Xaa1Xaa2=Thr-Thr, Gly-His and Glu-His- (SEQ ID NO:4)
• or a spacer selected from the group consisting of beta-alanyl, 5-amino-valeroyl, 4-amino-cyclohexanoyl, 4-amino-butyroyl, 6-amino-caproyl and derivatives thereof, wherein the carbon chain may be substituted or unsubstituted, saturated or unsaturated, hydroxylated or non-hydroxylated, sulfurated or non-sulfurated, (SEQ ID NO:5).