Target type: molecularfunction
Catalysis of the reaction: thiocyanate (SCN-) + hydrogen peroxide (H2O2) = hypothiocyanite (OSCN-) + 2 H2O. Catalyzes the hydrogen peroxide oxidation of thiocyanate. [GOC:pm, PMID:12626341]
Thiocyanate peroxidase activity catalyzes the oxidation of thiocyanate (SCN-) to thiocyanogen (SCN)2 by hydrogen peroxide (H2O2). This reaction is a crucial step in the detoxification of cyanide (CN-) in various organisms, including bacteria, plants, and animals.
The enzyme typically utilizes heme as a cofactor, which facilitates the transfer of electrons from thiocyanate to hydrogen peroxide. The reaction mechanism involves the following steps:
1. The enzyme binds both thiocyanate and hydrogen peroxide.
2. Hydrogen peroxide oxidizes the heme iron, forming a ferryl species (Fe(IV)=O).
3. The ferryl species oxidizes thiocyanate, producing thiocyanogen.
4. The enzyme releases thiocyanogen and is ready to catalyze another reaction.
Thiocyanogen is a highly reactive compound that can further react with other substrates, including glutathione and cyanide. This reactivity is essential for the detoxification of cyanide, as it prevents cyanide from binding to mitochondrial cytochrome c oxidase, a key enzyme in cellular respiration.
Thiocyanate peroxidase activity is also involved in other biological processes, such as the regulation of thyroid hormone synthesis and the defense against oxidative stress. The enzyme's role in these processes underscores its importance in maintaining cellular homeostasis and organismal health.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| Lactoperoxidase | A lactoperoxidase that is encoded in the genome of cow. [OMA:P80025, PRO:DNx] | Bos taurus (cattle) |
| Lactoperoxidase | A lactoperoxidase that is encoded in the genome of human. [PRO:DNx, UniProtKB:P22079] | Homo sapiens (human) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| gallic acid | gallate : A trihydroxybenzoate that is the conjugate base of gallic acid. | trihydroxybenzoic acid | antineoplastic agent; antioxidant; apoptosis inducer; astringent; cyclooxygenase 2 inhibitor; EC 1.13.11.33 (arachidonate 15-lipoxygenase) inhibitor; geroprotector; human xenobiotic metabolite; plant metabolite |
| hydralazine | hydralazine : The 1-hydrazino derivative of phthalazine; a direct-acting vasodilator that is used as an antihypertensive agent. Hydralazine: A direct-acting vasodilator that is used as an antihypertensive agent. | azaarene; hydrazines; ortho-fused heteroarene; phthalazines | antihypertensive agent; vasodilator agent |
| metoclopramide | metoclopramide : A member of the class of benzamides resulting from the formal condensation of 4-amino-5-chloro-2-methoxybenzoic acid with the primary amino group of N,N-diethylethane-1,2-diamine. Metoclopramide: A dopamine D2 antagonist that is used as an antiemetic. | benzamides; monochlorobenzenes; substituted aniline; tertiary amino compound | antiemetic; dopaminergic antagonist; environmental contaminant; gastrointestinal drug; xenobiotic |
| methyl gallate | methyl 3,4,5-trihydroxybenzoate : A gallate ester obtained by the formal condensation of gallic acid with methanol. It exhibits anti-oxidant, anti-tumor, anti-microbial and anti-inflammatory properties. methyl gallate: has both immunosuppressive and phytogenic antineoplastic activities; isolated from Acer saccharinum | gallate ester | anti-inflammatory agent; antioxidant; plant metabolite |
| carbimazole | carbimazole : A member of the class of imidazoles that is methimazole in which the nitrogen bearing a hydrogen is converted into its ethoxycarbonyl derivative. A prodrug for methimazol, carbimazole is used for the treatment of hyperthyroidism. Carbimazole: An imidazole antithyroid agent. Carbimazole is metabolized to METHIMAZOLE, which is responsible for the antithyroid activity. | 1,3-dihydroimidazole-2-thiones; carbamate ester | antithyroid drug; prodrug |
| epigallocatechin gallate | (-)-epigallocatechin 3-gallate : A gallate ester obtained by the formal condensation of gallic acid with the (3R)-hydroxy group of (-)-epigallocatechin. epigallocatechin gallate: a steroid 5alpha-reductase inhibitor and antimutagen in green tea (Camellia sinensis) | flavans; gallate ester; polyphenol | antineoplastic agent; antioxidant; apoptosis inducer; geroprotector; Hsp90 inhibitor; neuroprotective agent; plant metabolite |
| salicylhydroxamic acid | hydroxamic acid; phenols | antibacterial drug; EC 1.11.2.2 (myeloperoxidase) inhibitor; EC 3.5.1.5 (urease) inhibitor; trypanocidal drug | |
| epicatechin | (-)-epicatechin : A catechin with (2R,3R)-configuration. | catechin; polyphenol | antioxidant |
| gallocatechol | (-)-epigallocatechin : A flavan-3,3',4',5,5',7-hexol having (2R,3R)-configuration. | catechin; flavan-3,3',4',5,5',7-hexol | antioxidant; food component; plant metabolite |
| procyanidin b2 | procyanidin B2 : A proanthocyanidin consisting of two molecules of (-)-epicatechin joined by a bond between positions 4 and 8' in a beta-configuration. Procyanidin B2 can be found in Cinchona pubescens (Chinchona, in the rind, bark and cortex), in Cinnamomum verum (Ceylon cinnamon, in the rind, bark and cortex), in Crataegus monogyna (Common hawthorn, in the flower and blossom), in Uncaria guianensis (Cat's claw, in the root), in Vitis vinifera (Common grape vine, in the leaf), in Litchi chinensis (litchi, in the pericarp), in the apple, in Ecdysanthera utilis and in red wine. | biflavonoid; hydroxyflavan; polyphenol; proanthocyanidin | antioxidant; metabolite |
| proanthocyanidin a2 | proanthocyanidin A2 : A proanthocyanidin obtained by the condensation of (-)-epicatechin units. procyanidin A2: structure in first source | hydroxyflavan; proanthocyanidin | angiogenesis modulating agent; anti-HIV agent; antioxidant; metabolite |
| procyanidin C1 | procyanidin C1 : A proanthocyanidin consisting of three (-)-epicatechin units joined by two successive (4beta->8)-linkages. procyanidin trimer C1: a flavonoid found in multiple plant sources including grape, apple, and cacao, which has antioxidant and anti-inflammatory properties | hydroxyflavan; polyphenol; proanthocyanidin | anti-inflammatory agent; antioxidant; EC 1.17.3.2 (xanthine oxidase) inhibitor; EC 3.2.1.20 (alpha-glucosidase) inhibitor; lipoxygenase inhibitor; metabolite |
| 1,3,6-tri-o-galloyl-beta-d-glucose | 1,3,6-tri-O-galloylglucose: structure in first source | ||
| methimazole | methimazole : A member of the class of imidazoles that it imidazole-2-thione in which a methyl group replaces the hydrogen which is attached to a nitrogen. Methimazole: A thioureylene antithyroid agent that inhibits the formation of thyroid hormones by interfering with the incorporation of iodine into tyrosyl residues of thyroglobulin. This is done by interfering with the oxidation of iodide ion and iodotyrosyl groups through inhibition of the peroxidase enzyme. | 1,3-dihydroimidazole-2-thiones | antithyroid drug |
| chlorogenic acid | caffeoylquinic acid: Antiviral Agent; structure in first source chlorogenate : A monocarboxylic acid anion that is the conjugate base of chlorogenic acid; major species at pH 7.3. | cinnamate ester; tannin | food component; plant metabolite |
| quercetin | 7-hydroxyflavonol; pentahydroxyflavone | antibacterial agent; antineoplastic agent; antioxidant; Aurora kinase inhibitor; chelator; EC 1.10.99.2 [ribosyldihydronicotinamide dehydrogenase (quinone)] inhibitor; geroprotector; phytoestrogen; plant metabolite; protein kinase inhibitor; radical scavenger | |
| apigenin | Chamomile: Common name for several daisy-like plants (MATRICARIA; TRIPLEUROSPERMUM; ANTHEMIS; CHAMAEMELUM) native to Europe and Western Asia, now naturalized in the United States and Australia. | trihydroxyflavone | antineoplastic agent; metabolite |
| ellagic acid | catechols; cyclic ketone; lactone; organic heterotetracyclic compound; polyphenol | antioxidant; EC 1.14.18.1 (tyrosinase) inhibitor; EC 2.3.1.5 (arylamine N-acetyltransferase) inhibitor; EC 2.4.1.1 (glycogen phosphorylase) inhibitor; EC 2.5.1.18 (glutathione transferase) inhibitor; EC 2.7.1.127 (inositol-trisphosphate 3-kinase) inhibitor; EC 2.7.1.151 (inositol-polyphosphate multikinase) inhibitor; EC 2.7.4.6 (nucleoside-diphosphate kinase) inhibitor; EC 2.7.7.7 (DNA-directed DNA polymerase) inhibitor; EC 5.99.1.2 (DNA topoisomerase) inhibitor; EC 5.99.1.3 [DNA topoisomerase (ATP-hydrolysing)] inhibitor; food additive; fungal metabolite; geroprotector; plant metabolite; skin lightening agent |