2,6-Pyridinedicarboxylic acid (PDC, Dipicolinic acid) is a major component of bacterial endospores, comprising 5-15% of the spore dry weight, and is important for spore stability and resistance properties. 2,6-Pyridinedicarboxylic acid and its derivatives are introduced as a new sensitizer system for enzyme-amplified lanthanide luminescence (EALL), a detection scheme for bioassays, which combines enzymatic amplification with time-resolved luminescence measurements of lanthanide chelates.