The synthesis of a peptide having the structure attributed to a sound habituating material

A peptide isolated from rats habituated to a sound stimulus has been given the structure (see article) Glu-Ala-Gly-Tyr-Ser-Lys-OH. A synthesis of this compound afforded a product that different from the natural material on the basis of chromatographic and physiological comparisons. The proposed sequence must therefore be in error.