5-oxo-L-prolyl-L-histidyl-L-tryptophyl-L-seryl-L-tyrosyl-1-benzyl-D-histidyl-L-leucyl-L-arginyl-N-ethyl-L-prolinamide
5-oxo-L-prolyl-L-histidyl-L-tryptophyl-L-seryl-L-tyrosyl-Nτ-benzyl-D-histidyl-L-leucyl-L-arginyl-N-ethyl-L-prolinamide