Conoidin A is a covalent inhibitor of peroxiredoxin II with IC50 value of 23 μM [2].

Peroxiredoxins are a widely conserved family of enzymes that function in antioxidant defense and signal transduction, and changes in PrxII expression are associated with a variety of human diseases, including cancer [1].

Conoidin A is a novel, cell-permeable and covalent peroxiredoxin II inhibitor with IC50 value of 23 μM [1][2]. Conoidin A bound covalently to the peroxidatic cysteine of the T. gondii enzyme peroxiredoxin II (TgPrxII), inhibiting its enzymatic activity. In human epithelial cells, Conoidin A inhibited hyperoxidation of human PrxII [1]. Conoidin A also inactivated AcePrx-1 (a peroxiredoxin from the hookworm Ancylostoma ceylanicum) by alkylating or crosslinking the catalytic cysteines with IC50 value of 374 μM [2]. Conoidin A inhibited the hyperoxidation of two mammalian peroxiredoxin homologues (PrxI and PrxII) in cells [3].

References:
[1].? Haraldsen JD1, Liu G, Botting CH, et al. IDENTIFICATION OF CONOIDIN A AS A COVALENT INHIBITOR OF PEROXIREDOXIN II. Org Biomol Chem. 2009;7:3040-3048.
[2].? Nguyen JB1, Pool CD, Wong CY, et al. Peroxiredoxin-1 from the human hookworm Ancylostoma ceylanicum forms a stable oxidized decamer and is covalently inhibited by conoidin A. Chem Biol. 2013 Aug 22;20(8):991-1001.
[3].? Liu G, Botting CH, Evans KM, et al. Optimisation of conoidin A, a peroxiredoxin inhibitor. ChemMedChem. 2010 Jan;5(1):41-5.