N-(5-Carboxypentyl)maleimide2,5-Dihydro-2,5-dioxo-1H-pyrrole-1-hexanoic Acidε-Maleimidocaproic Acid6-Maleimidocaproic AcidEMCAN-(5-Carboxy-n-pentyl)maleimideε-Maleimidohexanoic Acid6-Maleimidohexanoic Acid6-(2,5-Dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanoic Acid