Reduction of sulfenic acids by ascorbate in proteins, connecting thiol-dependent to alternative redox pathways.

Sulfenic acids are the primary product of thiol oxidation by hydrogen peroxide and other oxidants. Several aspects of sulfenic acid formation through thiol oxidation were established recently. In contrast, the reduction of sulfenic acids is still scarcely investigated.

Amperometric microsensor based on nanoporous gold for ascorbic acid detection in highly acidic biological extracts.

Tuning the electrocatalytic properties of high surface area porous metallic frameworks like Nanoporous Gold (NPG) by tailoring the structure is a convenient strategy to design electrochemical sensors. Accordingly, an NPG-based sensitive, selective and robust electroanalytical platform was designed for the detection of ascorbic acid (AA) in acidic extracts of Aspergillus fumigatus fungus and Arabidopsis thaliana leaves. NPG films were electrodeposited on a gold microelectrode by potentiostatic electrodeposition and characterized by electron microscopy techniques, which confirmed the morphology and highly porous structure resembling nanowires-type pure gold fractals.

Non-Mammalian Prdx6 Enzymes (Proteins with 1-Cys Prdx Mechanism) Display PLA₂ Activity Similar to the Human Orthologue.

Mammalian peroxiredoxin class 6 (Prdx6) are bifunctional enzymes. Non-mammalian Prdx6 enzymes display Cys-based peroxidase activity, but to date their putative phospholipase A₂ (PLA₂ activities) has not been experimentally investigated. Initially, we observed that five non-mammalian Prdx6 enzymes (enzymes from (AtPER1), (TaPER1), (PaLsfA) and (AfPrx1 and AfPrxC)) present features compatible with PLA₂ activities in mammalian Prdx6 by amino acid sequences alignment and tertiary structure modeling.

Genetic inactivation of the phospholipase A activity of peroxiredoxin 6 in mice protects against LPS-induced acute lung injury.

Peroxiredoxin 6 (Prdx6) is a multifunctional enzyme that serves important antioxidant roles by scavenging hydroperoxides and reducing peroxidized cell membranes. Prdx6 also plays a key role in cell signaling by activating the NADPH oxidase, type 2 (Nox2) through its acidic Ca-independent phospholipase A2 (aiPLA2) activity. Nox2 generation of O, in addition to signaling, can contribute to oxidative stress and inflammation such as during sepsis-induced acute lung injury (ALI).

Analyses of the three 1-Cys Peroxiredoxins from Aspergillus fumigatus reveal that cytosolic Prx1 is central to HO metabolism and virulence.

Standing among the front defense strategies against pathogens, host phagocytic cells release various oxidants. Therefore, pathogens have to cope with stressful conditions at the site of infection. Peroxiredoxins (Prx) are highly reactive and abundant peroxidases that can support virulence and persistence of pathogens in distinct hosts.

Monitoring HO inside Aspergillus fumigatus with an Integrated Microelectrode: The Role of Peroxiredoxin Protein Prx1.

Peroxiredoxins (Prx) are important proteins involved in hydroperoxide degradation and are related to virulence in several pathogens, including Aspergillus fumigatus. In this work, in vivo studies on the degradation of hydrogen peroxide (HO) in the microenvironment of A. fumigatus fungus were performed by using an integrated Pt microelectrode.