Table 1

AhpC activity of native and variant AhpC proteinsa

AhpC proteinAhpC activity (nmoles NADPH oxidized/min/mg protein)
Native†216 ± 22
Native, oxidized†5 ± 5
Native, oxidized, Msr added†242 ± 5
Native, Msr added†244 ± 22
Native‡144 ± 22
Variant M101I‡23 ± 7
Variant M133I‡57 ± 15
Variants M101I and M133I‡8 ± 7
  • a AhpC activity was measured in a coupled assay by monitoring thioredoxin reductase-dependent oxidation of NADPH at 340 nm. “native” refers to the protein as purified from E. coli. † and ‡ indicate 2 independent sets of experiments done with different batches of native AhpC, Trx1, and TrxR. Data represent means and standard deviations from 4 replicates (†) or 10 to 15 replicates (‡).