scholarly journals Incorporation of [18O]water in the formation of p-hydroxybenzyl alcohol by the p-cresol methylhydroxylase from Pseudomonas putida

1978 ◽  
Vol 175 (1) ◽  
pp. 345-347 ◽  
Author(s):  
D J Hopper
Keyword(s):  
Oxygen Atom ◽  
Pseudomonas Putida ◽  
Methyl Group ◽  
Hydroxybenzyl Alcohol

In the hydroxylation of the methyl group of p-cresol by an enzyme from Pseudomonas putida the oxygen atom is derived from water. Although a second reaction by the same enzyme converts the product, p-hydroxybenzyl alcohol, into the aldehyde, the alcohol is an enzyme-free intermediate.

scholarly journals The purification and properties of p-cresol-(acceptor) oxidoreductase (hydroxylating), a flavocytochrome from Pseudomonas putida

1977 ◽  
Vol 167 (1) ◽  
pp. 155-162 ◽  
Author(s):  
D J Hopper ◽  
D G Taylor
Keyword(s):  
Pseudomonas Putida ◽  
Particulate Material ◽  
The Other ◽  
Methyl Group ◽  
Purification And Properties ◽  
Weight One ◽  
Dehydrogenation Reactions ◽  
Phenazine Methosulphate ◽  
Hydroxybenzyl Alcohol

The enzyme that catalyses the hydroxylation of the methyl group of p-cresol was purified from Pseudomonas putida. It has mol.wt. 115000 and appears to contain two subunits of equal molecular weight. One subunit is a c-type cytochrome and the other is a flavoprotein. Reduction of the cytochrome occurred on addition of substrate. The same enzyme catalyses both p-cresol hydroxylation and the further oxidation of the product, 4-hydroxybenzyl alcohol. The stoicheiometry of acceptor reduced per molecule of substrate oxidized is that for two dehydrogenation reactions. The Km for p-cresol is 7.3 × 10(-6) M and that for 4-hydroxybenzyl alcohol is 47.6 × 10(-6) M. The enzyme, which is assayed with phenazine methosulphate as electron acceptor, was stimulated by particulate material, which probably contains the acceptor in vivo.

Application of Laser-Excited Raman Spectroscopy to Organic Chemistry. II. Conformers of Some Isochromans

1970 ◽  
Vol 24 (1) ◽  
pp. 42-43 ◽  
Author(s):  
Stanley K. Freeman
Keyword(s):  
Organic Chemistry ◽  
Raman Spectroscopy ◽  
Oxygen Atom ◽  
Aromatic Ring ◽  
Raman Spectra ◽  
Liquid State ◽  
Methyl Group ◽  
Methyl Analog

Raman spectra of 4-methyl isochroman and its aromatic ring substituted derivatives indicate the presence of two conformers in the liquid state and only one in the solid, while the 1- and 3-methyl analog assume one conformation only in both states. The presence of a methyl group adjacent to the ring oxygen atom sterically prevents adoption of one of the two possible conformations due to 1,3-interaction. No such restriction is imposed on the 4-methyl compounds.

scholarly journals Rational Protein Engineering of Bacterial N-Demethylases to Create Biocatalysts for the Production of Methylxanthines

2021 ◽  
Author(s):  
Shelby Brooks Mills ◽  
Meredith B Mock ◽  
Ryan M Summers
Keyword(s):  
Protein Engineering ◽  
Pseudomonas Putida ◽  
Point Mutations ◽  
Attractive Alternative ◽  
Methyl Groups ◽  
Specific Point ◽  
Whole Cell ◽  
Methyl Group ◽  
E Coli ◽  
Rich History

Methylxanthines have a rich history as therapeutics and pharmaceuticals. However, natural dimethyl- and monomethylxanthines are difficult to produce synthetically, which has limited further exploration of these compounds in medicinal applications. A biosynthetic method for production of methylxanthines from whole cell biocatalysts is an attractive alternative. The bacterium Pseudomonas putida CBB5 contains a set of five enzymes, NdmABCDE, which are responsible for methylxanthine metabolism via N-demethylation to xanthine. The recent elucidation of the crystal structures of NdmA and NdmB, which remove the N1- and N3- methyl groups of caffeine, respectively, has opened new avenues to create biocatalysts for methylxanthine production. We have created a set of fifteen N-demethylase mutants and expressed them in E. coli BL21(DE3) as whole cell biocatalysts. The activity of each mutant was characterized for their affinity towards caffeine, theobromine, and theophylline. Two mutant enzymes in particular, labeled NdmA3 and NdmA4, both exhibited selectivity towards the N3-methyl group instead of the N1-methyl group. We also discovered that specific point mutations in NdmD resulted in the ability to tune the rate of the N-demethylase reaction. These new enzymes provide the capability of producing high-value methylxanthines, such as paraxanthine and 1-methylxanthine, through a biocatalytic route.

scholarly journals The aromatic alcohol dehydrogenases in Pseudomonas putida N.C.I.B. 9869 grown on 3,5-xylenol and p-cresol

1978 ◽  
Vol 175 (2) ◽  
pp. 659-667 ◽  
Author(s):  
M J Keat ◽  
D J Hopper
Keyword(s):  
Alcohol Dehydrogenase ◽  
Pseudomonas Putida ◽  
The Other ◽  
Alcohol Dehydrogenases ◽  
Whole Cells ◽  
Aromatic Alcohol ◽  
Aromatic Alcohols ◽  
Hydroxybenzyl Alcohol

Whole cells of Pseudomonas putida N.C.I.B 9869, when grown on either 3,5-xylenol or p-cresol, oxidized both m- and p-hydroxybenzyl alcohols. Two distinct NAD+-dependent m-hydroxybenzyl alcohol dehydrogenases were purified from cells grown on 3,5-xylenol. Each is active with a range of aromatic alcohols, including both m- and p-hydroxybenzyl alcohol, but differ in their relative rates with the various substrates. An NAD+-dependent alcohol dehydrogenase was also partially purified from p-cresol grown cells. This too was active with m- and p-hydroxybenzyl alcohol and other aromatic alcohols, but was not identical with either of the other two dehydrogenases. All three enzymes were unstable, but were stabilized by dithiothreitol and all were inhibited with p-chloromercuribenzoate. All were specific for NAD+ and each was shown to catalyse conversion of alcohol into aldehyde.

scholarly journals Biotransformation of Sesquiterpenoids from Liverworts by Fungi and Mammals

2010 ◽  
Vol 5 (5) ◽  
pp. 1934578X1000500 ◽  
Author(s):  
Yoshinori Asakawa ◽  
Toshihiro Hashimoto ◽  
Yoshiaki Noma
Keyword(s):  
Oxygen Atom ◽  
Bioactive Compounds ◽  
Higher Plants ◽  
Cyclopropane Ring ◽  
Primary Alcohol ◽  
Methyl Group ◽  
Secondary Hydroxyl ◽  
Cyclopentane Ring ◽  
One Step ◽  
Cytochrome P 450

Biotransformation of sesquiterpenoids isolated from several liverworts using various fungi and mammals is summarized. Microorganisms introduce an oxygen atom at an allylic position to give secondary hydroxyl and keto groups. The cyclopentane ring is also oxidized to afford monoketo, and mono- and diols. Double bonds are also either reduced or oxidized to give either saturated compounds or epoxides, followed by hydrolysis to afford diols. The methyl group is oxidized to give a primary alcohol. Some fungi cleave the cyclopropane ring to form a 1,1-dimethyl group. These reactions precede stereo- and regio-specifically. Cytochrome P-450 is responsible for the introduction of an oxygen function into the substrates. The present methods are cheap, one step reactions, non-hazardous, and very useful for the production of some bioactive compounds from a large number of terpenoids found in liverworts and higher plants.

scholarly journals Crystal structures of trans-acetyldicarbonyl(η5-cyclopentadienyl)(1,3,5-triaza-7-phosphaadamantane)molybdenum(II) and trans-acetyldicarbonyl(η5-cyclopentadienyl)(3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane)molybdenum(II)

2020 ◽  
Vol 76 (4) ◽  
pp. 547-551 ◽  
Author(s):  
Mitchell R. Anstey ◽  
John L. Bost ◽  
Anna S. Grumman ◽  
Nicholas D. Kennedy ◽  
Matthew T. Whited
Keyword(s):  
Oxygen Atom ◽  
Dominant Role ◽  
Molecular Structures ◽  
Carbonyl Groups ◽  
Methyl Group ◽  
Extended Structure ◽  
Carbonyl Ligands ◽  
Cyclopentadienyl Ligand ◽  
Migratory Insertion ◽  
Neighboring Molecule

The title compounds, [Mo(C5H5)(COCH3)(C6H12N3P)(CO)2], (1), and [Mo(C5H5)(COCH3)(C9H16N3O2P)(C6H5)2))(CO)2], (2), have been prepared by phosphine-induced migratory insertion from [Mo(C5H5)(CO)3(CH3)]. The molecular structures of these complexes are quite similar, exhibiting a four-legged piano-stool geometry with trans-disposed carbonyl ligands. The extended structures of complexes (1) and (2) differ substantially. For complex (1), the molybdenum acetyl unit plays a dominant role in the organization of the extended structure, joining the molecules into centrosymmetrical dimers through C—H...O interactions with a cyclopentadienyl ligand of a neighboring molecule, and these dimers are linked into layers parallel to (100) by C—H...O interactions between the molybdenum acetyl and the cyclopentadienyl ligand of another neighbor. The extended structure of (2) is dominated by C—H...O interactions involving the carbonyl groups of the acetamide groups of the DAPTA ligand, which join the molecules into centrosymmetrical dimers and link them into chains along [010]. Additional C—H...O interactions between the molybdenum acetyl oxygen atom and an acetamide methyl group join the chains into layers parallel to (101).

Cresol metabolism by the sulfate-reducing bacteriumDesulfotomaculumsp. strain Groll

1999 ◽  
Vol 45 (6) ◽  
pp. 458-463 ◽  
Author(s):  
Kathleen L Londry ◽  
Joseph M Suflita ◽  
Ralph S Tanner
Keyword(s):  
Aromatic Compounds ◽  
Enzyme Activities ◽  
Culture Fluid ◽  
Anaerobic Biodegradation ◽  
Oxidation Reactions ◽  
Methyl Group ◽  
Sulfate Reducing ◽  
Reducing Conditions ◽  
Ortho Cresol ◽  
Hydroxybenzyl Alcohol

The metabolism of cresols under sulfate-reducing conditions was investigated in Desulfotomaculum sp. strain Groll. This strain grows on a variety of aromatic compounds, including para- and meta- but not ortho-cresol. Degradation of p-cresol proceeded by oxidation reactions of the methyl group to yield p-hydroxybenzoate, which was then dehydroxylated to benzoate. The aromatic intermediates expected for this pathway, p-hydroxybenzyl alcohol, p-hydroxybenzaldehyde, p-hydroxybenzoate, and benzoate, were readily metabolized by strain Groll. Utilization of these intermediates generally preceded and inhibited the degradation of p-cresol. p-Hydroxybenzoate and benzoate were detected in culture fluid as metabolites of p-cresol. p-Hydroxybenzaldehyde and p-hydroxybenzoate were detected in cultures degrading p-hydroxybenzyl alcohol. Enzyme activities responsible for utilization of p- and m-cresol, induced by growth on the respective cresol, were detected in cell-free extracts of strain Groll. The compounds detected in culture fluids and the enzyme activities detected in cell-free extracts indicate that the pathways for the degradation of p- and m-cresol converge on benzoate, followed by metabolism to benzoyl-coenzyme A (CoA). Strain Groll can utilize both cresol isomers under sulfate-reducing conditions by similar reactions, but the enzyme activities catalyzing these transformations of the two isomers appear distinct.Key words: anaerobic biodegradation, sulfate reduction, Desulfotomaculum, p-cresol, m-cresol, o-cresol, benzoylCoA.

On the reduction of the ozonides of selected phenylethylenes by triphenylphosphine

1969 ◽  
Vol 47 (7) ◽  
pp. 1113-1116 ◽  
Author(s):  
Jacques Carles ◽  
Sándor Fliszár
Keyword(s):  
Oxygen Atom ◽  
Phenyl Group ◽  
The Other ◽  
Methyl Group ◽  
Oxygen Atoms

Triphenylphosphine has been found to reduce 18O labelled ozonides of styrene, stilbene, β-methylstyrene, and triphenylethylene by a very selective attack on the peroxidic oxygen atoms of the ozonides. The presence of ln electron withdrawing phenyl group attached to a C atom of the ozonide ring enhlnces the attack on the peroxidic oxygen adjacent to this C atom, whereas the presence of an electron releasing methyl group enhances the attack on the other peroxidic oxygen atom.

A theoretical study of adduct formation between methanolate and Propan-2-one

1981 ◽  
Vol 34 (6) ◽  
pp. 1189 ◽  
Author(s):  
JC Sheldon
Keyword(s):  
Hydrogen Bond ◽  
Oxygen Atom ◽  
Ab Initio ◽  
Molecular Orbital ◽  
Theoretical Study ◽  
Adduct Formation ◽  
Molecular Orbital Calculations ◽  
Carbonyl Carbon ◽  
Methyl Group ◽  
Methoxide Anion

Ab initio molecular orbital calculations at the STO-3G level of approximation predict that the methoxide anion bonds through its oxygen atom to form complexes with acetone in at least three different ways: (i) A tetrahedral adduct at the carbonyl carbon (ΔE -262 kJ mol-1). (ii) A hydrogen-bond complex with a single hydrogen of one methyl group (- 100 kJ mol-1). (iii) A symmetrical bidentate hydrogen-bond complex with a hydrogen from each acetone methyl group (- 143 kJ mol-1).

scholarly journals Proton-Nuclear Magnetic Resonance Analyses of the Substrate Specificity of a β-Ketolase from Pseudomonas putida, Acetopyruvate Hydrolase

1999 ◽  
Vol 181 (16) ◽  
pp. 5051-5059 ◽  
Author(s):  
Diana Pokorny ◽  
Lothar Brecker ◽  
Mateja Pogorevc ◽  
Walter Steiner ◽  
Herfried Griengl ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Pseudomonas Putida ◽  
Carbon Bond ◽  
Methyl Group ◽  
Solution Structures ◽  
H Nmr ◽  
Carbon Carbon Bond ◽  
Single Reaction

ABSTRACT A revised purification of acetopyruvate hydrolase from orcinol-grown Pseudomonas putida ORC is described. This carbon-carbon bond hydrolase, which is the last inducible enzyme of the orcinol catabolic pathway, is monomeric with a molecular size of ∼38 kDa; it hydrolyzes acetopyruvate to equimolar quantities of acetate and pyruvate. We have previously described the aqueous-solution structures of acetopyruvate at pH 7.5 and several synthesized analogues by1H-nuclear magnetic resonance (NMR)-Fourier transform (FT) experiments. Three 1H signals (2.2 to 2.4 ppm) of the methyl group are assigned unambiguously to the carboxylate anions of 2,4-diketo, 2-enol-4-keto, and 2-hydrate-4-keto forms (40:50:10). A1H-NMR assay for acetopyruvate hydrolase was used to study the kinetics and stoichiometries of reactions within a single reaction mixture (0.7 ml) by monitoring the three methyl-group signals of acetopyruvate and of the products acetate and pyruvate. Examination of 4-tert-butyl-2,4-diketobutanoate hydrolysis by the same method allowed the conclusion that it is the carboxylate 2-enol form(s) or carbanion(s) that is the actual substrate(s) of hydrolysis. Substrate analogues of 2,4-diketobutanoate with 4-phenyl or 4-benzyl groups are very poor substrates for the enzyme, whereas the 4-cyclohexyl analogue is readily hydrolyzed. In aqueous solution, the arene analogues do not form a stable 2-enol structure but exist principally as a delocalized π-electron system in conjugation with the aromatic ring. The effects of several divalent metal ions on solution structures were studied, and a tentative conclusion that the enol forms are coordinated to Mg2+ bound to the enzyme was made. 1H–2H exchange reactions showed the complete, fast equilibration of 2H into the C-3 of acetopyruvate chemically; this accounts for the appearance of2H in the product pyruvate. The C-3 of the product pyruvate was similarly labelled, but this exchange was only enzyme catalyzed; the methyl group of acetate did not undergo an exchange reaction. The unexpected preference for bulky 4-alkyl-group analogues is discussed in an evolutionary context for carbon-carbon bond hydrolases. Routine one-dimensional 1H-NMR in normal1H2O is a new method for rapid, noninvasive assays of enzymic activities to obtain the kinetics and stoichiometries of reactions in single reaction mixtures. Assessments of the solution structures of both substrates and products are also shown.

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