Table I

List of the most abundant modifications found in human A431 cell lysate and denoted in Fig. 2 Modification types are derived from UniMod (12).

PeakΔMElemental compositionModification typesAmino acid
A−48.003371−CH4SLoss from internal methionineMet
B−17.026549−NH3Oxobutanoic acid from N-terminal ThrThr
Pyro-Glu from GlnGln
Pyruvic acid from N-terminal SerSer
S-Carbamoylmethylcysteine cyclization (N-terminus)N terminus
C−2.015650−H2DidehydroSer, Tyr
Threonine oxidation to 2-amino-3-oxo-butanoic acidThr
D0.984016+ODeamidationAsn, Gln
−NH
E14.015650+CH2MethylationCys, His, Lys, Asn, Gln, Arg, Ile, Leu, N terminus
Methyl esterAsp, Glu
F15.994915+OOxidationMet, His, Trp
G27.994915+COFormylationLys, Ser, Thr, N terminus
H28.031300+C2H4EthylationLys, Glu, N terminus
DimethylationLys, Arg, Asn, N terminus
I31.989829+O2DihydroxyPro, Arg, Lys, Phe
J57.021464+C2H3NOCarbamidomethylCys, Lys, His, Asp, Glu, N terminus