H-Cys-Ser-Cys-Lys-Asp-Met-Thr-Asp-Lys-Glu-Cys-Leu-Asn-Phe-Cys-His-Gln-Asp-Val-Ile-Trp-OH (Disulfide bonds between Cys¹ and Cys¹⁵/Cys³ and Cys¹¹)