hypohalous acid

hypohalous acid

[hī¦pöt·ə·ləs ′as·əd]
(inorganic chemistry)
An oxyacid of a halogen (fluorine, chlorine, bromine, iodine, or astatine) possessing the general chemical formula HOX, where X is the halogen atom.
References in periodicals archive ?
8,975,220 B1; Clorox has patented a composition that consists of a homopolymer of diallyl dimethyl ammonium chloride; an oxidant selected from the group consisting of a hypohalous acid, a hypohalite, and mixtures thereof; water; and optionally, an adjuvant selected from the group consisting of a fragrance, a hydrotrope, a colorant, a dye, a buffer, a chelating agent, an electrolyte, an antimicrobial agent, a solvent, a stain and soil repellent, a lubricant, an odor control agent, a perfume, a fragrance release agent, an acid, a base, a solubilizing material, a stabilizer, an anti-corrosion agent, a thickener, a defoamer, a cloud-point modifier, a preservative, a water immiscible solvent, an enzyme, and mixtures thereof.
It might seem easier to produce hypothiocyanite chemically in in vitro applications, but producing hypothiocyanite chemically from the oxidation of [SCN.sup.-] by a halogen ([Cl.sub.2] or [Br.sub.2]) or by a hypohalous acid (HOCl or HOBr) in basic media is tricky due to overoxidation of [SCN.sup.-] [66].
The oxidative strength of [I.sub.2] is between that of the corresponding hypohalous acid HOI and the hypoiodite ion [OI.sup.-] and ranks as follows: 0.485 V (OI-) < 0.536 V ([I.sub.2]) < 0.987 V (HOI) [66].
[SCN.sup.-] is the two-electron donor with the lowest reduction potential and therefore forms the hypothiocyanite acid with the lowest oxidative power compared to hypohalous acids. Hypohalous acids rank as follows, with increasing oxidative strength: [OSCN.sup.-] < [OI.sup.-] < [OBr.sup.-] < [OCl.sup.-] [28, 66].
Ruegger, "On the irreversible destruction of reduced nicotinamide nucleotides by hypohalous acids," Archives of Biochemistry and Biophysics, vol.
One way that the phagosomes then destroy microbes is to create a supply of superoxide anions, which starts a cascade of reactions that produces hydrogen peroxide and then more toxic molecules, such as hydroxyl radical and hypohalous acid.
MPO catalyzes the reaction of hydrogen peroxide ([H.sub.2][O.sub.2]), formed by dismutation of [O.sub.2.sup.*-], and halide and pseudohalide ions ([Cl.sup.-], [Br.sup.-], and [SCN.sup.-]) to the corresponding hypohalous acids (hypochlorous acid, HOCl; hypobromous acid, HOBr; and hypothiocyanous acid, HOSCN) [16] and formation of other reactive intermediates such as reactive nitrogen species and tyrosyl radicals (Figure 1).
Reactions of hypohalous acids with proteins contribute to protein unfolding and enzyme inactivation.
Neutrophil-derived antiinfective agents Preformed granule Newly synthesised reactive Proteins * oxygen and nitrogen species Bactericidal proteins Superoxide Defensins (HNP1-4) Hydrogen peroxide LL-37 Hypohalous acids Myeloperoxidase Hydroxyl radical Proteinases (cathepsins, Singlet molecular elastase, proteinase-3) oxygen Secretory phospholipase Nitric oxide [A.sub.2]