Oxidation of Alcohols to Carboxylic Acids via Isolated Aldehydes

Tojo, Gabriel; Fernández, Marcos D.

doi:10.1007/0-387-35432-8_7

Cited by 113 publications

(149 citation statements)

References 11 publications

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“…The amount of uronic acid seemed to increase by increasing the dosage of RaOx and reaction time. Chemical oxidation procedures, where the oxidation to carboxylic acid proceeds by oxidizing the hydrate, such as TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl)-mediated reactions, are reported to produce either aldehydes or carboxylic acids, depending on the reaction conditions (47).…”

Section: Characterization Of a Novel Raffinose Oxidasementioning

confidence: 99%

A Novel Colletotrichum graminicola Raffinose Oxidase in the AA5 Family

Andberg

Mollerup

Parikka

et al. 2017

Appl Environ Microbiol

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We describe here the identification and characterization of a copper radical oxidase from auxiliary activities family 5 (AA5_2) that was distinguished by showing preferential activity toward raffinose. Despite the biotechnological potential of carbohydrate oxidases from family AA5, very few members have been characterized. The gene encoding raffinose oxidase from Colletotrichum graminicola (CgRaOx; EC 1.1.3.Ϫ) was identified utilizing a bioinformatics approach based on the known modular structure of a characterized AA5_2 galactose oxidase. CgRaOx was expressed in Pichia pastoris, and the purified enzyme displayed the highest activity on the trisaccharide raffinose, whereas the activity on the disaccharide melibiose was three times lower and more than ten times lower activity was detected on D-galactose at a 300 mM substrate concentration. Thus, the substrate preference of CgRaOx was distinguished clearly from the substrate preferences of the known galactose oxidases. The site of oxidation for raffinose was studied by 1 H nuclear magnetic resonance and mass spectrometry, and we confirmed that the hydroxyl group at the C-6 position was oxidized to an aldehyde and that in addition uronic acid was produced as a side product. A new electrospray ionization mass spectrometry method for the identification of C-6 oxidized products was developed, and the formation mechanism of the uronic acid was studied. CgRaOx presented a novel activity pattern in the AA5 family.IMPORTANCE Currently, there are only a few characterized members of the CAZy AA5 protein family. These enzymes are interesting from an application point of view because of their ability to utilize the cheap and abundant oxidant O 2 without the requirement of complex cofactors such as FAD or NAD(P). Here, we present the identification and characterization of a novel AA5 member from Colletotrichum graminicola. As discussed in the present study, the bioinformatics approach using the modular structure of galactose oxidase was successful in finding a C-6 hydroxyl carbohydrate oxidase having substrate preference for the trisaccharide raffinose. By the discovery of this activity, the diversity of the CAZy AA5 family is increasing.KEYWORDS CAZy AA5, galactose oxidase, nuclear magnetic resonance, NMR, carbohydrate, EC 1.1.3.Ϫ E nzymes that cleave or form oligo-and polysaccharides are classified in the sequence-based carbohydrate-active enzyme database (CAZy [http://www.cazy .org]). The sequences are linked to information about functionality (e.g., substrate specificity) and three-dimensional structure. The CAZy database was recently expanded to account for redox enzymes, leading to the auxiliary activities (AA) group. Currently, 13 AA families exist, comprising lignolytic oxidoreductases (families AA1, -2, -4, and -6), lytic polysaccharide monooxygenases (families AA9, -10, -11, and -13), carbohydrate

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Section: Characterization Of a Novel Raffinose Oxidasementioning

confidence: 99%

A Novel Colletotrichum graminicola Raffinose Oxidase in the AA5 Family

Andberg

Mollerup

Parikka

et al. 2017

Appl Environ Microbiol

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“…33,34) Encouraged by the novel aspect of the proposed reaction mechanisms for the H-D exchange reaction of alcohols (Section 2, Chart 5), we have focused on the development of dehydrogenative oxidation of alcohols into carbonyl products. Since the oxidation of alcohols traditionally required toxic and/or explosive oxidizing agents, 35) heterogeneously catalyzed dehydrogenation reactions are spotlighted as clean oxidation methods generating only H 2 utilized as the reductant in organic synthesis and energy sources. However, organic solvents have been required for the reported methods.…”

Section: Site-selective Deuteration Of Alcohols and Its Application Tmentioning

confidence: 99%

New Gateways to the Platinum Group Metal-Catalyzed Direct Deuterium-Labeling Method Utilizing Hydrogen as a Catalyst Activator

et al. 2018

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Deuterium-labeled compounds are widely utilized in various scientific fields. We summarize the recent advances in the direct deuteration of sugar, saturated fatty acid, and arene derivatives using heterogeneous platinum group metal on carbon catalysts by our research group. Hydrogen gas is a key catalyst-activator to facilitate the present H-D exchange reactions. In this review, the direct activation method of catalysts using in situ-generated hydrogen based on the dehydrogenation of alcohols is introduced. The obtained multiple deuterium-labeled products, including bioactive compounds, are expected to contribute to the development of many scientific investigations.

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“…The selective oxidation of alcohols into aldehydes or ketones is one of the most important transformations in organic syntheses [1], especially the oxidation of unsaturated alcohols into the corresponding unsaturated carbonyl compounds, e.g. the conversion of geraniol or nerol into geranial or neral, and the conversion of cinnamyl alcohol into cinnamaldehyde.…”

Section: Introductionmentioning

confidence: 99%

Selective and Efficient Oxidation of Unsaturated Alcohols as Constituents in Essential Oils

Thi

2018

JST

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Essential oil unsaturated alcohols have been oxidized efficiently into the corresponding unsaturated aldehydes by potassium permanganate supported copper(II) sulfate pentahydrate. Unsaturated aldehydes such as geranial and cinnamaldehyde being valuable components in food, cosmetic, perfumery and pharmaceutical chemistry, have been obtained in good yields (> 60%) under two activation methods: microwave irradiation and conventional heating.

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Oxidation of Alcohols to Carboxylic Acids via Isolated Aldehydes

Cited by 113 publications

References 11 publications

A Novel Colletotrichum graminicola Raffinose Oxidase in the AA5 Family

A Novel Colletotrichum graminicola Raffinose Oxidase in the AA5 Family

New Gateways to the Platinum Group Metal-Catalyzed Direct Deuterium-Labeling Method Utilizing Hydrogen as a Catalyst Activator

Selective and Efficient Oxidation of Unsaturated Alcohols as Constituents in Essential Oils

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