Herein we report the synthesis and the evaluation of eight novel compounds as irreversible inhibitors of transglutaminase (TGase). These compounds are based on a minimal peptidic scaffold shown previously [Chem. Biol. 2005, 12, 469–475] to confer affinity for the TGase active site and bear electrophilic groups such as α, β-unsaturated amide, chloroacetamide or maleimide; their general structure being Cbz-Phe-spacer-electrophile. The affinity ...