MS/MS Ion series of diadducted model peptides by naphthoquinones at pH 8.5.

Product ion spectra for adducted peptides were indistinguishable between both pH conditions; more products were observed at pH 8.5 therefore ions series for the products at this pH was given.
aObserved signals assigned as b- or y- ions for the diadducts are listed.
bReference to detailed spectra corresponding to the appropriate ion series.
cThe modifications are 1,2-naphthoquinone (monoadduct mass +158.04).
dThe adducted masses were observed in incubations performed at both pHs; data are from pH 8.5 incubations.
eIons in bold represent modification by a naphthoquinone. A bold b- or y- represents a monoadducted ion. Some of the diadduct MS/MS spectra had monoadduct fragment ions present that were absent in the monoadduct MS/MS spectra.
fThe modifications are 1,4-naphthoquinone (monoadduct mass +158.04).
gIn the detected fragment ion signals, X represents the mass of the adduct.