Hydroxylation and Dihydroxylation

Holland, Herbert L.

doi:10.1002/9783527620906.ch10

Cited by 9 publications

(4 citation statements)

References 296 publications

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“…The "non-epoxide" mechanism comprises a porphyrin proton shuttle and contributes, in addition to the non-enzymatic hydrolysis of arene oxides, to the formation of ketones and Figure 10. Selected aromatic hydroxylations catalyzed by P450s (according to review articles of Sono et al [88], Holland [14], Lewis [84], and Ortiz de Montellano and Voss [115]). Conversion of monoaromatic compounds (1 -7): (1) benzene hydroxylation yielding phenol and hydroquinone, (2) hydroxylation of toluene to p-and o-cresols, (3) aniline hydroxylation leading to 4-and 2-aminophenols, (4) benzoate hydroxylation at para-position, (5) hydroxylation of p-nitrophenol to 4-nitrocatechol, (6) para-hydroxylation of 2-chlorophenyl acetic acid, (7) specific hydroxylation of heterocyclic nicotinic acid to 6-hydroxynicotinic acid.…”

Section: Topicmentioning

confidence: 99%

“…2006.htm). Many of these enzymes, found in all kingdoms of life (archaea, eubacteria, eukaryota) [81 -83], catalyze hydroxylations and epoxidations of a wide range of substrates including aromatic compounds from simple benzene to complex ring systems such as flavonoids or aromatic steroids [14]. In addition to oxygen transfers, P450s are responsible for at least 20 other chemical reactions including dealkylation, S-and N-oxidations, alcohol and aldehyde oxidations, as well as dehalogenation and denitration [84].…”

Section: Heme Monooxygenases (P450s)mentioning

confidence: 99%

“…Recent advances in oxygenase-catalyzed biotransformations with biotechnological background have been reviewed by Van Beilen et al [11], Urlacher and Schmid [12], and Bernhardt [13]. Monooxygenases and dioxygenases can be distinguished from the introduction of either one or two oxygen atoms into the substrate [14]. The majority of "natural" oxygenases uses dioxygen (O 2 , a stable diradical = triplet oxygen) as an oxygen source but there are also a few enzymes in plants and fungi, which can act as peroxygenases transferring peroxide-oxygen (from hydrogen peroxide or organic peroxides).…”

Section: Introductionmentioning

confidence: 98%

“…Enzymes of the former subclass do not need external hydrogen donors (e.g., NAD[P]H) for oxygenation and act on single substrate molecules, while the latter act on paired hydrogen donors. There are monooxygenases and dioxygenases in both subclasses and their sub-subclasses were re-classified in 1984 by the EC leading in both cases to the deletion of all sub-subclasses from 1 to 10, and hence the first subsubclasses of oxygenases are now EC 1.13.11 and EC 1.14.11 (Enzyme nomenclature 1984 [15], Holland 1998 [14]; for details see: http://www.chem.qmul.ac.uk/iubmb/enzyme/ [the official page of the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology; last update March 13, 2006]). Furthermore, there are enzymes showing hydroxylating side activities such as tyrosinase (EC 1.10.3.1) or certain peroxidases (1.11.1.-).…”

Section: Introductionmentioning

confidence: 99%

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Enzymatic hydroxylation of aromatic compounds

Ullrich

Hofrichter

2007

Cell. Mol. Life Sci.

309

182

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Selective hydroxylation of aromatic compounds is among the most challenging chemical reactions in synthetic chemistry and has gained steadily increasing attention during recent years, particularly because of the use of hydroxylated aromatics as precursors for pharmaceuticals. Biocatalytic oxygen transfer by isolated enzymes or whole microbial cells is an elegant and efficient way to achieve selective hydroxylation. This review gives an overview of the different enzymes and mechanisms used to introduce oxygen atoms into aromatic molecules using either dioxygen (O(2)) or hydrogen peroxide (H(2)O(2)) as oxygen donors or indirect pathways via free radical intermediates. In this context, the article deals with Rieske-type and alpha-keto acid-dependent dioxygenases, as well as different non-heme monooxygenases (di-iron, pterin, and flavin enzymes), tyrosinase, laccase, and hydroxyl radical generating systems. The main emphasis is on the heme-containing enzymes, cytochrome P450 monooxygenases and peroxidases, including novel extracellular heme-thiolate haloperoxidases (peroxygenases), which are functional hybrids of both types of heme-biocatalysts.

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Section: Topicmentioning

confidence: 99%

Section: Heme Monooxygenases (P450s)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Enzymatic hydroxylation of aromatic compounds

Ullrich

Hofrichter

2007

Cell. Mol. Life Sci.

309

182

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The Concept of Docking and Protecting Groups in Biohydroxylation

Raadt¹,

Griengl²,

Weber³

2001

Chem. Eur. J.

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The hydroxylation of unactivated carbon atoms employing methods developed in the realms of classical organic chemistry is difficult to achieve and the processes available lack the degree of chemo-, regio- and enantioselectivity required for organic synthesis. To improve this situation, the concept of docking/protecting groups should enable the organic chemist to employ biohydroxylation as an easy tool for preparative work. Similar to the common practice of using protective groups in organic chemistry, a docking/protecting (d/p) group is introduced first, then the biotransformation is performed, and finally the d/p group is removed. The aim of this concept is not only to avoid time consuming microorganism screening methods, but also to improve hydroxylation position predictability, prevent undesired side reactions, aid substrate detection, and product recovery. This approach is successfully applied to carboxylic acids, ketones, aldehydes, and alcohols.

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