Haloperoxidase-Catalyzed Luminol Luminescence
Common peroxidase action and haloperoxidase action are quantifiable as light emission from dioxygenation of luminol (5-amino-2,3-dihydrophthalazine-1,4-dione). The velocity of enzyme action is dependent on the concentration of reactants. Thus, the reaction order of each participant reactant in lumin...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-03-01
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| Series: | Antioxidants |
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| Online Access: | https://www.mdpi.com/2076-3921/11/3/518 |
| _version_ | 1827650119959314432 |
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| author | Robert C. Allen |
| author_facet | Robert C. Allen |
| author_sort | Robert C. Allen |
| collection | DOAJ |
| description | Common peroxidase action and haloperoxidase action are quantifiable as light emission from dioxygenation of luminol (5-amino-2,3-dihydrophthalazine-1,4-dione). The velocity of enzyme action is dependent on the concentration of reactants. Thus, the reaction order of each participant reactant in luminol luminescence was determined. Horseradish peroxidase (HRP)-catalyzed luminol luminescence is first order for hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>), but myeloperoxidase (MPO) and eosinophil peroxidase (EPO) are second order for H<sub>2</sub>O<sub>2</sub>. For MPO, reaction is first order for chloride (Cl<sup>−</sup>) or bromide (Br<sup>−</sup>). For EPO, reaction is first order for Br<sup>−</sup>. HRP action has no halide requirement. For MPO and EPO, reaction is first order for luminol, but for HRP, reaction is greater than first order for luminol. Haloperoxidase-catalyzed luminol luminescence requires acidity, but HRP action requires alkalinity. Unlike the radical mechanism of common peroxidase, haloperoxidases (XPO) catalyze non-radical oxidation of halide to hypohalite. That reaction is second order for H<sub>2</sub>O<sub>2</sub> is consistent with the non-enzymatic reaction of hypohalite with a second H<sub>2</sub>O<sub>2</sub> to produce singlet molecular oxygen (<sup>1</sup>O<sub>2</sub>*) for luminol dioxygenation. Alternatively, luminol dehydrogenation by hypohalite followed by reaction with H<sub>2</sub>O<sub>2</sub> yields dioxygenation consistent with the same reaction order. Haloperoxidase action, Cl<sup>−</sup>, and Br<sup>−</sup> are specifically quantifiable as luminol luminescence in an acidic milieu. |
| first_indexed | 2024-03-09T20:10:56Z |
| format | Article |
| id | doaj.art-b12d3f1cbd0142d4984b4780ae0d98b5 |
| institution | Directory Open Access Journal |
| issn | 2076-3921 |
| language | English |
| last_indexed | 2024-03-09T20:10:56Z |
| publishDate | 2022-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Antioxidants |
| spelling | doaj.art-b12d3f1cbd0142d4984b4780ae0d98b52023-11-24T00:18:08ZengMDPI AGAntioxidants2076-39212022-03-0111351810.3390/antiox11030518Haloperoxidase-Catalyzed Luminol LuminescenceRobert C. Allen0Department of Pathology, Creighton University, Omaha, NE 68178, USACommon peroxidase action and haloperoxidase action are quantifiable as light emission from dioxygenation of luminol (5-amino-2,3-dihydrophthalazine-1,4-dione). The velocity of enzyme action is dependent on the concentration of reactants. Thus, the reaction order of each participant reactant in luminol luminescence was determined. Horseradish peroxidase (HRP)-catalyzed luminol luminescence is first order for hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>), but myeloperoxidase (MPO) and eosinophil peroxidase (EPO) are second order for H<sub>2</sub>O<sub>2</sub>. For MPO, reaction is first order for chloride (Cl<sup>−</sup>) or bromide (Br<sup>−</sup>). For EPO, reaction is first order for Br<sup>−</sup>. HRP action has no halide requirement. For MPO and EPO, reaction is first order for luminol, but for HRP, reaction is greater than first order for luminol. Haloperoxidase-catalyzed luminol luminescence requires acidity, but HRP action requires alkalinity. Unlike the radical mechanism of common peroxidase, haloperoxidases (XPO) catalyze non-radical oxidation of halide to hypohalite. That reaction is second order for H<sub>2</sub>O<sub>2</sub> is consistent with the non-enzymatic reaction of hypohalite with a second H<sub>2</sub>O<sub>2</sub> to produce singlet molecular oxygen (<sup>1</sup>O<sub>2</sub>*) for luminol dioxygenation. Alternatively, luminol dehydrogenation by hypohalite followed by reaction with H<sub>2</sub>O<sub>2</sub> yields dioxygenation consistent with the same reaction order. Haloperoxidase action, Cl<sup>−</sup>, and Br<sup>−</sup> are specifically quantifiable as luminol luminescence in an acidic milieu.https://www.mdpi.com/2076-3921/11/3/518haloperoxidasemyeloperoxidaseeosinophil peroxidasehorseradish peroxidasehalide oxidationsinglet molecular oxygen |
| spellingShingle | Robert C. Allen Haloperoxidase-Catalyzed Luminol Luminescence Antioxidants haloperoxidase myeloperoxidase eosinophil peroxidase horseradish peroxidase halide oxidation singlet molecular oxygen |
| title | Haloperoxidase-Catalyzed Luminol Luminescence |
| title_full | Haloperoxidase-Catalyzed Luminol Luminescence |
| title_fullStr | Haloperoxidase-Catalyzed Luminol Luminescence |
| title_full_unstemmed | Haloperoxidase-Catalyzed Luminol Luminescence |
| title_short | Haloperoxidase-Catalyzed Luminol Luminescence |
| title_sort | haloperoxidase catalyzed luminol luminescence |
| topic | haloperoxidase myeloperoxidase eosinophil peroxidase horseradish peroxidase halide oxidation singlet molecular oxygen |
| url | https://www.mdpi.com/2076-3921/11/3/518 |
| work_keys_str_mv | AT robertcallen haloperoxidasecatalyzedluminolluminescence |