histargin

Nα-[2-[[(S)-4-Guanidino-1-carboxybutyl]amino]ethyl]-L-histidine

(2S)-2-[2-[[(1S)-1-carboxy-2-(3H-imidazol-4-yl)ethyl]amino]ethylamino] -5-(diaminomethylideneamino)pentanoic acid