Activation enthalpies and pH dependence of phenol hydroxylase from <i>Trichosporon cutaneum</i>, in vitro and in situ

Mörtberg, M; Neujahr, Halina Y.

doi:10.1016/0014-5793(88)80988-8

Cited by 5 publications

(2 citation statements)

References 15 publications

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“…PHHY has the capacity to hydroxylate fluoro-, chloro-, amino-, and methyl-substituted phenols [105,106]. Similar to PHBH, the enzyme is not required to bind the phenol substrate for flavin to become reduced by NADPH, however, the affinity for NADPH and the rate constant for reduction increases with target substrate binding [107,108]. …”

Section: The Class a Fpmosmentioning

confidence: 99%

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Form Follows Function: Structural and Catalytic Variation in the Class A Flavoprotein Monooxygenases

Crozier-Reabe

Moran

2012

IJMS

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Flavoprotein monooxygenases (FPMOs) exhibit an array of mechanistic solutions to a common chemical objective; the monooxygenation of a target substrate. Each FPMO efficiently couples reduction of a flavin cofactor by NAD(P)H to oxygenation of the target substrate via a (hydro)peroxyflavin intermediate. This purpose of this review is to describe in detail the Class A flavoprotein hydroxylases (FPMO) in the context of the other FPMO classes (B–F). Both one and two component FPMOs are found in nature. Two-component enzymes require, in addition to the monooxygenase, the involvement of a reductase that first catalyzes the reduction of the flavin by NAD(P)H. The Class A and B FPMOs are single-component and manage to orchestrate the same net reaction within a single peptide. The Class A enzymes have, by some considerable margin, the most complete research record. These enzymes use choreographed movements of the flavin ring that facilitate access of the organic substrates to the active site, provide a means for interaction of NADPH with the flavin, offer a mechanism to sequester the dioxygen reduction chemistry from solvent and a means to release the product. The majority of the discrete catalytic events of the catalytic cycle can be observed directly in exquisite detail using spectrophotometric kinetic methods and many of the key mechanistic conclusions are further supported by structural data. This review attempts to compile each of the key observations made for both paradigm and newly discovered examples of Class A FPMOs into a complete catalytic description of one enzymatic turnover.

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Section: The Class a Fpmosmentioning

confidence: 99%

“…The first proposal suggested that substrate bound the enzyme in phenolate form, due to increase in affinity observed at higher pH values [108,109]. However, binding experiments using p -nitrophenol showed the neutral form binding to the oxidized enzyme [110].…”

Section: The Class a Fpmosmentioning

confidence: 99%

Form Follows Function: Structural and Catalytic Variation in the Class A Flavoprotein Monooxygenases

Crozier-Reabe

Moran

2012

IJMS

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Catabolism of benzene compounds by ascomycetous and basidiomycetous yeasts and yeastlike fungi

Middelhoven

1993

Antonie van Leeuwenhoek

154

112

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A literature review is given on growth of yeasts on benzene compounds and on the catabolic pathways involved. Additionally, a yeast collection was screened for assimilation of phenol and 3-hydroxybenzoic acid. Fifteen ascomycetous and thirteen basidiomycetous yeast species were selected and were tested for growth on 84 benzene compounds. It appeared that 63 of these compounds supported growth of one or more yeast species. The black yeast Exophiala jeanselmei assimilated 54 of these compounds. The catechol branch of the 3-oxoadipate pathway and its hydroxyhydroquinone variant were involved in phenol and resorcinol catabolism of ascomycetes as well as of basidiomycetes. However, these two groups of yeasts showed characteristic differences in hydroxybenzoate catabolism. In the yeastlike fungus E. jeanselmei and in basidiomycetes of the genera Cryptococcus, Leucosporidium and Rhodotorula, the protocatechuate branch of the 3-oxoadipate pathway was induced by growth on 3- and 4-hydroxybenzoic acids. In three Trichosporon species and in all ascomycetous yeasts tested, 4-hydroxybenzoic acid was catabolyzed via protocatechuate and hydroxyhydroquinone. These yeasts were unable to cleave protocatechuate. 3-Hydroxybenzoic and 3-hydroxycinnamic acids were catabolized in ascomycetous yeasts via the gentisate pathway, but in basidiomycetes via protocatechuate. Incomplete oxidation of phenol, some chlorophenols, cresols and xylenols was observed in cultures of Candida parapsilosis growing on hydroquinone. Most compounds transformed by the growing culture were also converted by the phenol monooxygenase present in cell-free extracts of this yeast. They did not support growth. The relationship between the ability of ascomycetous yeasts to assimilate n-alkanes, amines and benzene compounds, and the presence of Coenzyme Q9 is discussed.

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6-Mercapto-FAD and 6-thiocyanato-FAD as active site probes of phenol hydroxylase

Taylor¹,

Massey²

1991

Journal of Biological Chemistry

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Activation enthalpies and pH dependence of phenol hydroxylase from Trichosporon cutaneum, in vitro and in situ

Cited by 5 publications

References 15 publications

Form Follows Function: Structural and Catalytic Variation in the Class A Flavoprotein Monooxygenases

Form Follows Function: Structural and Catalytic Variation in the Class A Flavoprotein Monooxygenases

Catabolism of benzene compounds by ascomycetous and basidiomycetous yeasts and yeastlike fungi

6-Mercapto-FAD and 6-thiocyanato-FAD as active site probes of phenol hydroxylase

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