Chemical Reactivities of <i>ortho</i>-Quinones Produced in Living Organisms: Fate of Quinonoid Products Formed by Tyrosinase and Phenoloxidase Action on Phenols and Catechols
Tyrosinase catalyzes the oxidation of phenols and catechols (<i>o</i>-diphenols) to <i>o</i>-quinones. The reactivities of <i>o</i>-quinones thus generated are responsible for oxidative browning of plant products, sclerotization of insect cuticle, defense reaction...
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MDPI AG
2020-08-01
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| Series: | International Journal of Molecular Sciences |
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| author | Shosuke Ito Manickam Sugumaran Kazumasa Wakamatsu |
| author_facet | Shosuke Ito Manickam Sugumaran Kazumasa Wakamatsu |
| author_sort | Shosuke Ito |
| collection | DOAJ |
| description | Tyrosinase catalyzes the oxidation of phenols and catechols (<i>o</i>-diphenols) to <i>o</i>-quinones. The reactivities of <i>o</i>-quinones thus generated are responsible for oxidative browning of plant products, sclerotization of insect cuticle, defense reaction in arthropods, tunichrome biochemistry in tunicates, production of mussel glue, and most importantly melanin biosynthesis in all organisms. These reactions also form a set of major reactions that are of nonenzymatic origin in nature. In this review, we summarized the chemical fates of <i>o</i>-quinones. Many of the reactions of <i>o</i>-quinones proceed extremely fast with a half-life of less than a second. As a result, the corresponding quinone production can only be detected through rapid scanning spectrophotometry. Michael-1,6-addition with thiols, intramolecular cyclization reaction with side chain amino groups, and the redox regeneration to original catechol represent some of the fast reactions exhibited by <i>o</i>-quinones, while, nucleophilic addition of carboxyl group, alcoholic group, and water are mostly slow reactions. A variety of catecholamines also exhibit side chain desaturation through tautomeric quinone methide formation. Therefore, quinone methide tautomers also play a pivotal role in the fate of numerous <i>o</i>-quinones. Armed with such wide and dangerous reactivity, <i>o</i>-quinones are capable of modifying the structure of important cellular components especially proteins and DNA and causing severe cytotoxicity and carcinogenic effects. The reactivities of different <i>o</i>-quinones involved in these processes along with special emphasis on mechanism of melanogenesis are discussed. |
| first_indexed | 2024-03-10T16:56:51Z |
| format | Article |
| id | doaj.art-65220358760c4b08b01890c5590a8387 |
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| issn | 1661-6596 1422-0067 |
| language | English |
| last_indexed | 2024-03-10T16:56:51Z |
| publishDate | 2020-08-01 |
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| series | International Journal of Molecular Sciences |
| spelling | doaj.art-65220358760c4b08b01890c5590a83872023-11-20T11:07:22ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672020-08-012117608010.3390/ijms21176080Chemical Reactivities of <i>ortho</i>-Quinones Produced in Living Organisms: Fate of Quinonoid Products Formed by Tyrosinase and Phenoloxidase Action on Phenols and CatecholsShosuke Ito0Manickam Sugumaran1Kazumasa Wakamatsu2Department of Chemistry, Fujita Health University School of Medical Sciences, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 470-1192, JapanDepartment of Biology, University of Massachusetts, Boston, MA 02125, USADepartment of Chemistry, Fujita Health University School of Medical Sciences, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 470-1192, JapanTyrosinase catalyzes the oxidation of phenols and catechols (<i>o</i>-diphenols) to <i>o</i>-quinones. The reactivities of <i>o</i>-quinones thus generated are responsible for oxidative browning of plant products, sclerotization of insect cuticle, defense reaction in arthropods, tunichrome biochemistry in tunicates, production of mussel glue, and most importantly melanin biosynthesis in all organisms. These reactions also form a set of major reactions that are of nonenzymatic origin in nature. In this review, we summarized the chemical fates of <i>o</i>-quinones. Many of the reactions of <i>o</i>-quinones proceed extremely fast with a half-life of less than a second. As a result, the corresponding quinone production can only be detected through rapid scanning spectrophotometry. Michael-1,6-addition with thiols, intramolecular cyclization reaction with side chain amino groups, and the redox regeneration to original catechol represent some of the fast reactions exhibited by <i>o</i>-quinones, while, nucleophilic addition of carboxyl group, alcoholic group, and water are mostly slow reactions. A variety of catecholamines also exhibit side chain desaturation through tautomeric quinone methide formation. Therefore, quinone methide tautomers also play a pivotal role in the fate of numerous <i>o</i>-quinones. Armed with such wide and dangerous reactivity, <i>o</i>-quinones are capable of modifying the structure of important cellular components especially proteins and DNA and causing severe cytotoxicity and carcinogenic effects. The reactivities of different <i>o</i>-quinones involved in these processes along with special emphasis on mechanism of melanogenesis are discussed.https://www.mdpi.com/1422-0067/21/17/6080<i>o</i>-quinonesquinone methidesphenolscatecholstyrosinasethiols |
| spellingShingle | Shosuke Ito Manickam Sugumaran Kazumasa Wakamatsu Chemical Reactivities of <i>ortho</i>-Quinones Produced in Living Organisms: Fate of Quinonoid Products Formed by Tyrosinase and Phenoloxidase Action on Phenols and Catechols International Journal of Molecular Sciences <i>o</i>-quinones quinone methides phenols catechols tyrosinase thiols |
| title | Chemical Reactivities of <i>ortho</i>-Quinones Produced in Living Organisms: Fate of Quinonoid Products Formed by Tyrosinase and Phenoloxidase Action on Phenols and Catechols |
| title_full | Chemical Reactivities of <i>ortho</i>-Quinones Produced in Living Organisms: Fate of Quinonoid Products Formed by Tyrosinase and Phenoloxidase Action on Phenols and Catechols |
| title_fullStr | Chemical Reactivities of <i>ortho</i>-Quinones Produced in Living Organisms: Fate of Quinonoid Products Formed by Tyrosinase and Phenoloxidase Action on Phenols and Catechols |
| title_full_unstemmed | Chemical Reactivities of <i>ortho</i>-Quinones Produced in Living Organisms: Fate of Quinonoid Products Formed by Tyrosinase and Phenoloxidase Action on Phenols and Catechols |
| title_short | Chemical Reactivities of <i>ortho</i>-Quinones Produced in Living Organisms: Fate of Quinonoid Products Formed by Tyrosinase and Phenoloxidase Action on Phenols and Catechols |
| title_sort | chemical reactivities of i ortho i quinones produced in living organisms fate of quinonoid products formed by tyrosinase and phenoloxidase action on phenols and catechols |
| topic | <i>o</i>-quinones quinone methides phenols catechols tyrosinase thiols |
| url | https://www.mdpi.com/1422-0067/21/17/6080 |
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