Table 1.

Mass spectrometric evaluation of DJ-1 reacted with H₂O₂

Protein	Detected mass	Δmass, atomic mass units
WT	20,302
WT + H2O2	20,333	+32
	20,303
C106A mutant	20,270
C106A mutant + H2O2	20,270
C46A mutant	20,268
	20,299	+32
C46A mutant + H2O2	20,300	+32
C53A mutant	20,301	+32
	20,270
C53A mutant + H2O2	20,300	+32
	20,268
WT + H2O2+ arsenite	20,331	+32
	20,299
C53A mutant + H2O2 + arsenite	20,300	+32
	20,266
WT + H2O2 + GSH (5 mM)	20,303
	20,334	+32

The protein was reacted with H₂O₂, and changes in protein mass were determined by ESI/mass spectrometry. Detected masses are listed in order of relative abundance within the same treatment (SI Fig. 7). The C46A and C53A mutant proteins contained oxidized protein molecules without treatment with H₂O₂, indicating an increased sensitivity to oxidation. Δmass reflects the difference in mass relative to the unmodified protein. All detected masses have errors of no more than ±2 atomic mass units.