HEXAGLYCINE

GLY-GLY-GLY-GLY-GLY-GLY

H-GLY-GLY-GLY-GLY-GLY-GLY-OH

2-[[2-[[2-[[2-[[2-(glycylamino)acetyl]amino]acetyl]amino]acetyl]amino]acetyl]amino]acetic acid

2-[[2-[[2-[[2-[[2-[(2-aminoacetyl)amino]acetyl]amino]acetyl]amino]acetyl]amino]acetyl]amino]acetic acid

2-[2-[2-[2-[2-(2-azanylethanoylamino)ethanoylamino]ethanoylamino]ethanoylamino]ethanoylamino]ethanoic acid