AhpC

AhpC, alkyl hydroperoxide reductase C, is a bacterial antioxidant enzyme belonging to the peroxiredoxin family. It defends cells against oxidative stress by lowering hydrogen peroxide and organic hydroperoxides. The Helicobacter pylori enzyme can be used in as a research tool in microbial survival during inflammation.

AhpC catalysis relies on reactive cysteine residues. In H. pylori, cysteine 49 reacts with peroxide, while cysteine 169 participates in regeneration through formation of a disulfide bond between subunits. In laboratories, purified recombinant AhpC is used to investigate peroxide detoxification, substrate specificity, and reaction kinetics. A common activity assay combines AhpC with thioredoxin, thioredoxin reductase, NADPH, and a peroxide substrate. Researchers follow NADPH consumption by measuring decreasing absorbance at 340 nm. Comparing reaction rates under controlled conditions allows assessment of enzyme performance, substrate preference, and sensitivity to oxidation. Assays require suitable background controls because NADPH oxidation can also arise from other components.