Metallopeptide compositions for treatment of sexual dysfunction

A metallopeptide, consisting of a peptide of formula IV, V, VI or VII:

• wherein:
• R1 is NH2, NH3+, NH2—R7, R8—NH2 or H;
• R2 is H or a linear or branched C1 to C17 alkyl, aryl, heteroaryl, alkene, alkenyl, or aralkyl chain;
• R3 and R4 are independently a C1 to C6 aliphatic linear or branched chain, including CH3, or an aromatic amino acid side chain moiety, on the proviso that not more than one of R3 and R4 is a C1 to C6 aliphatic linear or branched chain;
• R5 is a C1 to C6 linear or branched chain or a neutral hydrogen bonding or positively charged amino acid side chain moiety;
• R6 is OH or NH2;
• R7 is from 1 to 3 amino acid residues, excluding residues with a side chain comprising indole, or a C1-C17 chain, including an alkyl, aryl, heteroaryl, alkene, alkenyl, or aralkyl, but excluding indole;
• R8 is an amino acid residue with an aliphatic side chain or its corresponding N-acylated derivative;
• R9 is H or CH3;
• S1 is an amino acid side chain moiety including a sulfur atom (S) for metal ion complexation;
• and
• the index value n is 0, in which case it is not present, or is 1;
• and
• a metal ion complexed to S in S1 and at least one preceding alpha amino nitrogen (N) atom, thereby displacing the hydrogen (H) in the alpha amino NH group.