Fig. 1. A generalized approach for capturing CoA-bound metabolites.

(A) A peptide with an N-terminal cysteine readily reacts with the thioester of CoA metabolites, creating a stable amide bond with the acyl group. After capture, the thiol of the peptide can then be used to immobilize the analyte and peptide onto a maleimide-presenting monolayer. (B) Five-hundred micromolar CoA conjugates of acetyl, acetoacetyl, HMG, and succinyl was reacted with the peptide CAK(Me₃)SA. The resulting SAMDI spectra show that all analytes can be efficiently detected. m/z, mass/charge ratio.