scholarly journals Microbial oxidation of amines. Partial purification of a trimethylamine mono-oxygenase from Pseudomonas aminovorans and its role in growth on trimethylamine

1974 ◽  
Vol 140 (2) ◽  
pp. 253-263 ◽  
Author(s):  
Christopher A. Boulton ◽  
M. James C. Crabbe ◽  
Peter J. Large

1. A mono-oxygenase, which oxidizes trimethylamine and other tertiary amines bearing methyl or ethyl groups, was partially purified sixfold from Pseudomonas aminovorans grown on trimethylamine as sole carbon source. 2. The preferred electron donor was NADPH. The enzyme had a pH optimum of 8.0–9.4 for trimethylamine oxidation, and 8.8–9.2 for dimethylamine oxidation. 3. The oxidation product of trimethylamine was shown to be trimethylamine N-oxide. Other tertiary amines were probably also converted into N-oxides. 4. The enzyme also oxidized secondary amines. 5. The oxidation of trimethylamine was only slightly inhibited by CO and not at all by KCN or proadifen hydrochloride (SKF 525-A), but was inhibited by trimethylsulphonium chloride, tetramethylammonium chloride, 2,4-dichloro-6-phenylphenoxyethylamine (Lilly 53325) and its NN-diethyl derivative (Lilly 18947). 6. The oxidation of dimethylamine showed a similar response to inhibitors and a parallel loss in activity on heating at 35°C. 7. The activities of the trimethylamine mono-oxygenase, trimethylamine N-oxide demethylase and the secondary-amine mono-oxygenase increased severalfold during adaptation of succinate-grown bacteria to growth on trimethylamine, and the trimethylamine mono-oxygenase was the first enzyme to show an increase in activity. It is concluded that all three enzymes are involved in growth on trimethylamine by this organism.

1971 ◽  
Vol 125 (2) ◽  
pp. 449-459 ◽  
Author(s):  
R. R. Eady ◽  
T. R. Jarman ◽  
P. J. Large

1. Crude extracts of Pseudomonas aminovorans grown on methylamine, di-methylamine, trimethylamine or trimethylamine N-oxide contain an enzyme or enzyme system catalysing the NADH- or NADPH- and oxygen-dependent oxidation of dimethylamine to methylamine and formaldehyde. 2. The enzyme has been partially purified about five-fold. It is unstable, but can be stabilized by addition of 5% (v/v) ethanol. 3. The partially purified enzyme will utilize either NADH (Km 6.5μm) or NADPH (Km 13.2μm): The following secondary amines have been shown to be substrates: dimethylamine, ethylmethylamine, diethylamine, methyl-n-propylamine, ethyl-n-propylamine, n-butylmethylamine and N-methylethanolamine. The Km values and comparative reaction rates for each substrate have been determined. Where the alkyl groups are different, the aldehyde products are derived from both groups. 4. The enzyme system has a pH optimum of 6.8 and is inhibited by mercurials, thiol compounds, cyanide and carbon monoxide. 5. The partially purified preparation had a spectral maximum at 412nm with shoulders at 427 and 550nm. Reduction with dithionite or NAD(P)H bleached the 412nm peak, and the shoulder at 427nm became a peak. Additional peaks appeared at 550 and 580–588nm. Reduction of a preparation bubbled with carbon monoxide enhanced and sharpened the Soret peak and caused it to shift to 422nm. 6. Analysis of the preparation showed the presence of flavin, acid-extractable iron and non-acid-extractable iron in the proportion 1.1:1.9:1. On reduction with dithionite or NADPH the preparation showed an electron-paramagnetic-resonance signal at around g=1.946.


2017 ◽  
Vol 52 (4) ◽  
pp. 263-272
Author(s):  
PC Okwuenu ◽  
AL Ezugwu ◽  
FC Chilaka

A Fourteen day experimental study was carried out to determine the day of highest glucoamylase activity using amylopectin from guinea corn starch as the sole carbon source. Two peaks of high activity were observed on the fifth and twelveth days, and were thus mass produced. Specific activities for crude enzymes were found to be 729.45 U/mg and 1046.82 U/mg for day five and twelve harvested enzymes respectively. Ammonium sulphate saturations, 70% and 20%, were found suitable to precipitate proteins with highest glucoamylase activity for day five and twelve harvested enzymes respectively. After ammonium sulphate precipitation and gel filtration, specific activities were found to be 65.98 U/mg and 180.52 U/mg respectively for day five harvested enzyme and 61.51 U/mg and 272.81 U/mg for day twelve harvested enzyme. The pH optimum for day five harvested enzyme were found to be 7.5, 7.5 and 6.0 using tiger nut, cassava and guinea corn starches as substrates respectively, also, the pH optimum for day twelve harvested enzyme were found to be 5.0, 8.5 and 7.0 using tiger nut, cassava and guinea corn starches as substrate, respectively. Optimum temperatures were found to be 50˚C and 45˚C for day five and twelve harvested enzymes, respectively. Km and Vmax, of day five harvested enzyme were found to be 770.75 mg/ml and 2500 μmol/min, 158.55 mg/ml and 500 μmol/min and 46.23 mg/ml and 454.53 μmol/min using cassava, guinea corn and tiger nut starches as substrate respectively. Km and Vmax of day twelve harvested enzyme were found to be 87.1 mg/ml and 384.61 μmol/min, 29.51 mg/ml and 243.90 μmol/min, and 2364 mg/ml and 2500 μmol/min, using cassava, guinea corn and tiger nut starches as substrate respectively.Bangladesh J. Sci. Ind. Res. 52(4), 263-272, 2017


1987 ◽  
Vol 52 (11) ◽  
pp. 2699-2709 ◽  
Author(s):  
Dalimil Dvořák ◽  
Zdeněk Arnold

Reaction of arylmethylenemalonaldehydes with tributylphosphine and tertiary amines affords compounds of dipolar structure whereas reaction with primary and secondary amines leads to 1,4-addition products. Salts of nucleophilic inorganic anions add to arylmethylenemalonaldehydes under formation of salts of substituted malonaldehydes.


Author(s):  
Vivek Kumar Ranjan ◽  
Shriparna Mukherjee ◽  
Subarna Thakur ◽  
Krutika Gupta ◽  
Ranadhir Chakraborty

2008 ◽  
Vol 5 (4) ◽  
pp. 367-374 ◽  
Author(s):  
Jing Wang ◽  
Guiwen Yan ◽  
Mingquan An ◽  
Jieli Liu ◽  
Houming Zhang ◽  
...  

1975 ◽  
Vol 25 (2) ◽  
pp. 119-135 ◽  
Author(s):  
Meryl Polkinghorne ◽  
M. J. Hynes

SUMMARYWild-type strains ofAspergillus nidulansgrow poorly onL-histidine as a sole nitrogen source. The synthesis of the enzyme histidase (EC. 4.3.1.3) appears to be a limiting factor in the growth of the wild type, as strains carrying the mutantareA102 allele have elevated histidase levels and grow strongly on histidine as a sole nitrogen source.L-Histidine is an extremely weak sole carbon source for all strains.Ammonium repression has an important role in the regulation of histidase synthesis and the relief of ammonium repression is dependent on the availability of a good carbon source. The level of histidase synthesis does not respond to the addition of exogenous substrate.Mutants carrying lesions in thesarA orsarB loci (suppressor ofareA102) have been isolated. The growth properties of these mutants on histidine as a sole nitrogen source correlate with the levels of histidase synthesized. Mutation at thesarA andsarB loci also reduces the utilization of a number of other nitrogen sources. The data suggest that these two genes may code for regulatory products involved in nitrogen catabolism. No histidase structural gene mutants were identified and possible explanations of this are discussed.


1985 ◽  
Vol 5 (5) ◽  
pp. 1111-1121
Author(s):  
S B Ellis ◽  
P F Brust ◽  
P J Koutz ◽  
A F Waters ◽  
M M Harpold ◽  
...  

The oxidation of methanol follows a well-defined pathway and is similar for several methylotrophic yeasts. The use of methanol as the sole carbon source for the growth of Pichia pastoris stimulates the expression of a family of genes. Three methanol-responsive genes have been isolated; cDNA copies have been made from mRNAs of these genes, and the protein products from in vitro translations have been examined. The identification of alcohol oxidase as one of the cloned, methanol-regulated genes has been made by enzymatic, immunological, and sequence analyses. Methanol-regulated expression of each of these three isolated genes can be demonstrated to occur at the level of transcription. Finally, DNA subfragments of two of the methanol-responsive genomic clones from P. pastoris have been isolated and tentatively identified as containing the control regions involved in methanol regulation.


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