Haptenation of Macrophage Migration Inhibitory Factor

Firstly, the adductome of the two major mouse blood proteins, as well as of the protein macrophage migration inhibitory factor (MIF) with the model hapten tetramethylrhodamine isothiocyanate (TRITC)was invastigated. After incubation at different molar ratios of TRITC, an untargeted Full MS/dd-MS2 experimental approach was used with a QExactive Quadrupole-Orbitrap mass spectrometer. The data were processed with Proteome Discoverer and the suggested sites of adductions were confirmed in parallel reaction monitoring mode (PRM) on the same instruments. Blood and lymph node samples of mise treated topically with the same hapten were screened for the peptides containing the most reactive sites of the aformentioned proteins. Only the adducted N-terminal peptide of the protein MIF could be detected. Thereafter, a quantification approach in PRM mode using standards was implemented to quantify this peptide, both modified and unmodified. Quantification was based in characteristic b and y ions.