AhpCF

AhpCF refers to the alkyl hydroperoxide reductase complex found in many bacteria. The system is composed of two components: AhpC, a peroxiredoxin that reduces peroxides, and AhpF, a flavoprotein disulfide reductase that provides reducing equivalents from NADH. Together, they form a detoxification pathway that protects cells from oxidative damage caused by hydrogen peroxide and organic hydroperoxides.

Mechanism and function are centered on electron transfer. Electrons from NADH are passed to the FAD prosthetic group in AhpF, which in turn reduces a disulfide in AhpF and ultimately transfers electrons to AhpC. Reduced AhpC can then reduce peroxide substrates to their corresponding alcohols, with AhpC returning to its oxidized form and ready to be reduced again by AhpF. This cycle allows rapid, localized peroxide neutralization, particularly under conditions of oxidative stress.

Regulation and expression are typically coordinated with cellular responses to reactive oxygen species. In many bacteria, ahpCF expression is upregulated by oxidative stress regulators such as OxyR, enabling a rapid increase in peroxide-detoxifying capacity when hydrogen peroxide levels rise. The genes for AhpC and AhpF are commonly located in an operon and can be co-transcribed.

Distribution and significance vary among organisms. The AhpCF system is widespread in Gram-negative bacteria and serves as a major component of the oxidative stress defense in parallel with catalases and other peroxidases. It contributes to survival in hostile or oxygen-rich environments and has been a subject of study for understanding bacterial stress responses and potential targets for antimicrobial strategies.