Aca-Bio is a specialized chemical probe designed for the specific enrichment and detection of lysine acetoacetylation (Kacac). Its core architecture consists of a hydroxylamine group, a polyethylene glycol (PEG) linker, and a biotin tag. Functionally, the hydroxylamine group selectively reacts with the unique ketone carbonyl moiety of Kacac under physiological conditions to form a stable, covalent oxime bond. This specific targeting allows Aca-Bio to accurately label Kacac-modified peptides in complex biological samples. Subsequently, the attached biotin tag enables efficient isolation of these labeled peptides via streptavidin-mediated affinity purification. A critical feature of Aca-Bio is its pH-responsive reversibility; the oxime bond remains stable at neutral pH but undergoes controlled cleavage in acidic environments. This allows for the gentle and effective elution of enriched peptides, facilitating subsequent mass spectrometry analysis. By overcoming the limitations of traditional antibody-based methods, Aca-Bio serves as a highly specific and sensitive tool for global Kacac substrate profiling.
