scholarly journals The thermochemical characterization of sodium dithionite, flavin mononucleotide, flavin-adenine dinucleotide and methyl and benzyl viologens as low-potential reductants for biological systems

1975 ◽  
Vol 152 (1) ◽  
pp. 33-37 ◽  
Author(s):  
G D Watts ◽  
A Burns
Keyword(s):  
Thermodynamic Data ◽  
Methyl Viologen ◽  
Flavin Adenine Dinucleotide ◽  
Sodium Dithionite ◽  
Flavin Mononucleotide ◽  
Heat Of Reaction ◽  
Calorimetric Data ◽  
Aqueous Buffer ◽  
Buffer Solutions

The heat of reaction (ΔH) of Fe(CN)63−, Methyl Viologen, FMN and FAD with S2O42− in aqueous buffer solutions was measured calorimetrically. In addition ΔH values for reduction of Fe(CN)63-, FMN and FAD by reduced Methyl Viologen were determined. The resulting calorimetric data and corresponding E0′ values were combined to yield thermodynamic data for these simple reducing agents in a form useful for applications to biological reactions. Thermodynamic data for the reduction of spinach ferredoxin are also presented.

scholarly journals A ferredoxin-dependent dihydropyrimidine dehydrogenase in Clostridium chromiireducens

2020 ◽  
Vol 40 (7) ◽  
Author(s):  
Feifei Wang ◽  
Yifeng Wei ◽  
Qiang Lu ◽  
Ee Lui Ang ◽  
Huimin Zhao ◽  
...  
Keyword(s):  
Anaerobic Bacterium ◽  
Methyl Viologen ◽  
Flavin Adenine Dinucleotide ◽  
Biochemical Characterization ◽  
Dihydropyrimidine Dehydrogenase ◽  
Anaerobic Bacteria ◽  
Gene Clusters ◽  
Flavin Mononucleotide ◽  
Pyrimidine Degradation

Abstract Dihydropyrimidine dehydrogenase (PydA) catalyzes the first step of the reductive pyrimidine degradation (Pyd) pathway in bacteria and eukaryotes, enabling pyrimidines to be utilized as substrates for growth. PydA homologs studied to date catalyze the reduction of uracil to dihydrouracil, coupled to the oxidation of NAD(P)H. Uracil reduction occurs at a flavin mononucleotide (FMN) site, and NAD(P)H oxidation occurs at a flavin adenine dinucleotide (FAD) site, with two ferredoxin domains thought to mediate inter-site electron transfer. Here, we report the biochemical characterization of a Clostridial PydA homolog (PydAc) from a Pyd gene cluster in the strict anaerobic bacterium Clostridium chromiireducens. PydAc lacks the FAD domain, and instead is able to catalyze uracil reduction using reduced methyl viologen or reduced ferredoxin as the electron source. Homologs of PydAc are present in Pyd gene clusters in many strict anaerobic bacteria, which use reduced ferredoxin as an intermediate in their energy metabolism.

scholarly journals Identification and Characterization of Catabolic para-Nitrophenol 4-Monooxygenase and para-Benzoquinone Reductase from Pseudomonas sp. Strain WBC-3

2009 ◽  
Vol 191 (8) ◽  
pp. 2703-2710 ◽  
Author(s):  
Jun-Jie Zhang ◽  
Hong Liu ◽  
Yi Xiao ◽  
Xian-En Zhang ◽  
Ning-Yi Zhou
Keyword(s):  
Gene Cluster ◽  
Flavin Adenine Dinucleotide ◽  
Gel Filtration ◽  
Sole Source ◽  
Open Reading Frames ◽  
Flavin Mononucleotide ◽  
Large Component ◽  
Identification And Characterization ◽  
Reading Frames

ABSTRACT Pseudomonas sp. strain WBC-3 utilizes para-nitrophenol (PNP) as a sole source of carbon, nitrogen, and energy. In order to identify the genes involved in this utilization, we cloned and sequenced a 12.7-kb fragment containing a conserved region of NAD(P)H:quinone oxidoreductase genes. Of the products of the 13 open reading frames deduced from this fragment, PnpA shares 24% identity to the large component of a 3-hydroxyphenylacetate hydroxylase from Pseudomonas putida U and PnpB is 58% identical to an NAD(P)H:quinone oxidoreductase from Escherichia coli. Both PnpA and PnpB were purified to homogeneity as His-tagged proteins, and they were considered to be a monomer and a dimer, respectively, as determined by gel filtration. PnpA is a flavin adenine dinucleotide-dependent single-component PNP 4-monooxygenase that converts PNP to para-benzoquinone in the presence of NADPH. PnpB is a flavin mononucleotide-and NADPH-dependent p-benzoquinone reductase that catalyzes the reduction of p-benzoquinone to hydroquinone. PnpB could enhance PnpA activity, and genetic analyses indicated that both pnpA and pnpB play essential roles in PNP mineralization in strain WBC-3. Furthermore, the pnpCDEF gene cluster next to pnpAB shares significant similarities with and has the same organization as a gene cluster responsible for hydroquinone degradation (hapCDEF) in Pseudomonas fluorescens ACB (M. J. Moonen, N. M. Kamerbeek, A. H. Westphal, S. A. Boeren, D. B. Janssen, M. W. Fraaije, and W. J. van Berkel, J. Bacteriol. 190:5190-5198, 2008), suggesting that the genes involved in PNP degradation are physically linked.

Structural Characterization of HP1264 Reveals a Novel Fold for the Flavin Mononucleotide Binding Protein

Biochemistry ◽  
2013 ◽  
Vol 52 (9) ◽  
pp. 1583-1593 ◽  
Author(s):  
Ki-Young Lee ◽  
Ji-Hun Kim ◽  
Kyu-Yeon Lee ◽  
Jiyun Lee ◽  
Ingyun Lee ◽  
...  
Keyword(s):  
Structural Characterization ◽  
Binding Protein ◽  
Flavin Mononucleotide

scholarly journals Gene Cloning and Molecular Characterization of a Two-Enzyme System Catalyzing the Oxidative Detoxification of β-Endosulfan

2002 ◽  
Vol 68 (12) ◽  
pp. 6237-6245 ◽  
Author(s):  
Tara D. Sutherland ◽  
Irene Horne ◽  
Robyn J. Russell ◽  
John G. Oakeshott
Keyword(s):  
Shuttle Vector ◽  
Open Reading Frame ◽  
Cosmid Library ◽  
Flavin Mononucleotide ◽  
Flavin Reductase ◽  
Reading Frame ◽  
Reductase Gene ◽  
Degradation Activity ◽  
Layer Chromatography

ABSTRACT The gram-positive bacterium Mycobacterium sp. strain ESD is able to use the cyclodiene insecticide endosulfan as a source of sulfur for growth. This activity is dependent on the absence of sulfite or sulfate in the growth medium. A cosmid library of strain ESD DNA was constructed in a Mycobacterium-Escherichia coli shuttle vector and screened for endosulfan-degrading activity in Mycobacterium smegmatis, a species that does not degrade endosulfan. Using this method, we identified a single cosmid that conferred sulfur-dependent endosulfan-degrading activity on the host strain. An open reading frame (esd) was identified within this cosmid that, when expressed behind a constitutive promoter in a mycobacterial expression vector, conferred sulfite- and sulfate-independent β-endosulfan degradation activity on the recombinant strain. The translation product of this gene (Esd) had up to 50% sequence identity with an unusual family of monooxygenase enzymes that use reduced flavins, provided by a separate flavin reductase enzyme, as cosubstrates. An additional partial open reading frame was located upstream of the Esd gene that had sequence homology to the same monooxygenase family. A flavin reductase gene, identified in the M. smegmatis genome, was cloned, expressed, and used to provide reduced flavin mononucleotide for Esd in enzyme assays. Thin-layer chromatography and gas chromatography analyses of the enzyme assay mixtures revealed the disappearance of β-endosulfan and the appearance of the endosulfan metabolites, endosulfan monoaldehyde and endosulfan hydroxyether. This suggests that Esd catalyzes the oxygenation of β-endosulfan to endosulfan monoaldehyde and endosulfan hydroxyether. Esd did not degrade either α-endosulfan or the metabolite of endosulfan, endosulfan sulfate.

Conjugation of 4-(dimethylamino)pyridine to primary amines in aqueous buffer solutions using an N-hydroxysuccinimide ester reagent

2021 ◽  
Vol 81 ◽  
pp. 153343
Author(s):  
Saki Horie ◽  
Hikaru Fujita ◽  
Rina Yamashita ◽  
Munetaka Kunishima
Keyword(s):  
Primary Amines ◽  
Aqueous Buffer ◽  
Buffer Solutions

scholarly journals Gamma Radiolysis of Flavin Mononucleotide and Flavin-Adenine Dinucleotide in Aqueous Solution

1991 ◽  
Vol 64 (8) ◽  
pp. 2532-2538 ◽  
Author(s):  
Abhijit Saha ◽  
Parikshit Chandra Mandal ◽  
Sudhindra Nath Bhattacharyya
Keyword(s):  
Aqueous Solution ◽  
Flavin Adenine Dinucleotide ◽  
Flavin Mononucleotide ◽  
Gamma Radiolysis
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