ONH(S)NHNONH(S)NHONH(S)HOONH(S)OHONH(R)OONH(S)CH3CH3ONH(S)OONH(S)NHHNNHON(R)NH-NHtBuNHNHTrpSerTyrD-SerLeuArgProHONHOHisCH3H3CH3CNH2ONH2OH3COOCH3