This isolation strategy, coupled with LC–MS–MS, allowed the identification of 417 discernible proteins with a statistically significant increase in adduction with increasing HNE exposure [44]. Western blot analysis of a subset of the streptavidin captured proteins showed adduction at HNE concentrations as low as 1 μM. Thus, the sensitivity of the biotin hydrazide–streptavidin capture and release approach allows a global analysis of electrophile-adducted proteins at physiologically relevant concentrations of HNE.