N-terminal N-acetyl-L-(Asp/Glu)3 residue
n-terminal n-acetyl-l-(asp/glu)3 residue
N-terminal <em>N</em>-acetyl tripeptidic residue, composed of acidic <small>L</small> amino-acid (<small>L</small>-Asp or <small>L</small>-Glu)