4-HNE adducts were identified on apo and holo rL-FABP via MALDI-TOF/TOF Mass Spectrometery.

<p>Following incubation with reactive aldehyde, rL-FABP was found to be modified in both the apo and holo form. MS/MS spectra from 4-HNE treated apo rL-FABP revealed the presence of two protein adducts, at residues Lys57 and Cys69. The same experiments were conducted with holo rL-FABP and revealed an additional four 4-HNE adducts on Lys31, Lys46, Lys6, and His 43. Identified b/y ions are labeled within the spectrum and shown along the peptide backbone above the spectrum. The parent ion of the MS/MS fragment is shown as an inset in the upper right corner of the spectrum.