On the role of purines in the enzymatic reduction of tetrazolium salts

1957 ◽  
Vol 13 (12) ◽  
pp. 476-477 ◽  
Author(s):  
T. L. Sourkes ◽  
J. R. Lagnado
Keyword(s):  
Tetrazolium Salts ◽  
Enzymatic Reduction

FURTHER OBSERVATIONS ON THE ENZYMATIC REDUCTION OF TETRAZOLIUM SALTS BY MONOAMINES

1958 ◽  
Vol 36 (6) ◽  
pp. 587-594 ◽  
Author(s):  
J. R. Lagnado ◽  
T. L. Sourkes
Keyword(s):  
Rat Liver ◽  
Metal Binding ◽  
Enzyme System ◽  
Enzymatic Reaction ◽  
Free Base ◽  
Tetrazolium Salts ◽  
Enzymatic Reduction ◽  
Tissue Homogenates ◽  
Cofactor Activity

Studies on the role of purines as cofactors in the enzymatic reduction of tetrazolium salts by monoamines have led to the following results: (1) With whole rat liver extracts as the source of enzymes, several purines exhibit cofactor activity either as the free base or as the corresponding riboside and ribotide derivatives. (2) In contrast to this, mitochondrial material from rat liver is active only if adenylic acid or one of several ribotidic derivatives containing an adenylyl or similar moiety is used as cofactor. (3) Mitochondrial material utilizes hypoxanthine as cofactor for the amine/tetrazolium system only in combination with the supernatant obtained by centrifugation of tissue homogenates at 20,000 g. The additional factor present in this supernatant portion is heat-labile and nondialyzable. The possibility that this additional factor is an enzyme or enzymes converting the free base to the ribotide is discussed.Inhibition studies have revealed that the amine/tetrazolium enzyme system is sensitive to several metal-binding agents, but no direct evidence for the role of a metal in the enzymatic reaction could be obtained. It was also found that nicotinamide and adenine, neither of which exhibits cofactor activity, are potent inhibitors of the enzyme system studied.

FURTHER OBSERVATIONS ON THE ENZYMATIC REDUCTION OF TETRAZOLIUM SALTS BY MONOAMINES

1958 ◽  
Vol 36 (1) ◽  
pp. 587-594 ◽  
Author(s):  
J. R. Lagnado ◽  
T. L. Sourkes
Keyword(s):  
Rat Liver ◽  
Metal Binding ◽  
Enzyme System ◽  
Enzymatic Reaction ◽  
Free Base ◽  
Tetrazolium Salts ◽  
Enzymatic Reduction ◽  
Tissue Homogenates ◽  
Cofactor Activity

Studies on the role of purines as cofactors in the enzymatic reduction of tetrazolium salts by monoamines have led to the following results: (1) With whole rat liver extracts as the source of enzymes, several purines exhibit cofactor activity either as the free base or as the corresponding riboside and ribotide derivatives. (2) In contrast to this, mitochondrial material from rat liver is active only if adenylic acid or one of several ribotidic derivatives containing an adenylyl or similar moiety is used as cofactor. (3) Mitochondrial material utilizes hypoxanthine as cofactor for the amine/tetrazolium system only in combination with the supernatant obtained by centrifugation of tissue homogenates at 20,000 g. The additional factor present in this supernatant portion is heat-labile and nondialyzable. The possibility that this additional factor is an enzyme or enzymes converting the free base to the ribotide is discussed.Inhibition studies have revealed that the amine/tetrazolium enzyme system is sensitive to several metal-binding agents, but no direct evidence for the role of a metal in the enzymatic reaction could be obtained. It was also found that nicotinamide and adenine, neither of which exhibits cofactor activity, are potent inhibitors of the enzyme system studied.

scholarly journals Mechanism of Two-/Four-Electron Reduction of Nitroaromatics by Oxygen-Insensitive Nitroreductases: The Role of a Non-Enzymatic Reduction Step

Molecules ◽  
2018 ◽  
Vol 23 (7) ◽  
pp. 1672 ◽  
Author(s):  
Benjaminas Valiauga ◽  
Lina Misevičienė ◽  
Michelle H. Rich ◽  
David F. Ackerley ◽  
Jonas Šarlauskas ◽  
...  
Keyword(s):  
Reduction Step ◽  
Enzymatic Reduction ◽  
Electron Reduction

Role of Selenium in the Enzymatic Reduction of Hydroperoxides

1998 ◽  
Vol 136 (1) ◽  
pp. 25-42 ◽  
Author(s):  
Leopold Flohé ◽  
Klaus-Dieter Aumann ◽  
Peter Steinert
Keyword(s):  
Enzymatic Reduction

Role of Glutamine in Metabolic and Epigenetic Reprogramming in AML

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2559-2559
Author(s):  
Juliana Vélez Luján ◽  
Niki Zacharias ◽  
Dinesh Rakheja ◽  
Tushar D Bhagat ◽  
Jaehyuk Lee ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Research Funding ◽  
Epigenetic Reprogramming ◽  
Cellular Growth ◽  
Hypoxic Conditions ◽  
Enhanced Production ◽  
Enzymatic Reduction ◽  
Isocitrate Dehydrogenase 2

Abstract Glutamine (Gln) was shown to play a role in generation of oncometabolite 2-hydroxyglutarate (2-HG) in tumors with high GLS (glutaminase) expression, whereby IDH2 (Isocitrate Dehydrogenase 2) enzyme catalyzes carboxylating reduction of glutamine-derived α-ketoglutarate (α-KG) to isocitrate and noncarboxylating reduction to 2-HG (Wise PNAS 2011). 2-HG in turn is known to inhibit α-KG dependent dioxygenases that mediate epigenetic events, including DNA and histone demethylation (Licht Cancer Cell 2010). A recent report demonstrated that hypoxia induces production of the L-enantiomer of 2-HG (L-2HG), through enzymatic reduction of α-KG by lactate dehydrogenase A (LDHA) (Intlekofer Cell Metabolism 2015). We have previously demonstrated that leukemic bone marrow microenvironment is highly hypoxic (Benito PLoS One 2011). Further, our unpublished data indicate upregulation of GLS protein and increase production of total 2-HG in AML (acute myeloid leukemia) cells cultured under hypoxia. We therefore propose a link between hypoxia, Gln metabolism, and epigenetic regulation in AML. Since increased methylation (and decreased hydroxymethylation) is seen in AML, we hypothesize that GLS inhibition can abrogate these changes via reduction of 2-HG levels. First, we examined effects of hypoxia and selective GLS inhibitor CB-839 (Calithera Biosciences) on cellular growth of AML cells with wild type IDH (OCI-AML3 and HL-60), cultured alone or co-cultured with bone marrow derived stromal cells (MSC). The culture of untreated OCI-AML3 alone in normoxic and hypoxic conditions caused a decrease in viability from 96 ± 2.5% to 84 ± 4.1% respectively, while the treatment with CB-839 (1 mM) for 6 days decreased viability in OCI-AML3 cells from 94 ± 0.23% to 71 ± 2.3% respectively (P=0.015). While MSC co-cultures improved survival of floating AML cells, the attached cells that were in direct contact with MSC were more affected under hypoxic conditions, having a viability of 64 ± 8.7% at the end of the experiment. These data indicate that GLS inhibitor is more effective under hypoxic conditions mimicking leukemic BM microenvironment. Hypoxia selectively induced the production of L-2HG (measured by liquid chromatography-tandem mass spectrometry) under hypoxic conditions (>40 fold) in OCI-AML3 cells, both with and without MSC co-culture. This increase in L-2HG was partially inhibited by co-treating OCI-AML3 cells with GLS inhibitor CB-839 (reduction of 1.7-fold in media only and 1.3-fold in MSC co-culture). Determination of hydroxymethylation (hmc) levels using HELP-GT assay demonstrated a significant increase in hmc in cells treated with CB-839. Of importance, genes that were differentially hydroxymethylated after CB-839 treatment belonged to important functional categories with cancer being the dominant pathway affected by these changes. Under hypoxia, glucose metabolism is known to be directed towards anaerobic glycolysis, with increased pyruvate-lactate enzymatic conversion by LDHA. To characterize the role of Gln and GLS on these processes within leukemia microenvironment, we performed nuclear magnetic resonance imaging with hyperpolarized pyruvate in NSG (NOD scid gamma) mice engrafted with GFP/luc-labeled OCI-AML3 cells. Inhibition of GLS in vivo following exposure of mice with 200 mg/kg dose of CB-839 showed a decrease in lactate conversion rate within leukemic bone marrow (femur area) (0.31 + 0.03 (pre) to 0.20 + 0.04 (post) P < 0.05), possibly due to the reduction of the level of NADH from decreased flux of Gln in the TCA cycle. In summary, our results indicate that Gln and GLS contribute towards hypoxia-induced production of L-2HG and critical epigenetic changes in AML; as well as playing a role in enhanced production of lactate from pyruvate. These findings suggest a major importance of Gln in metabolic and epigenetic reprogramming of microenvironment. Disclosures Off Label Use: CB-839 is a potent, selective, reversible and orally bioavailable glutaminase (mitochondrial enzyme able to convert glutamine in glutamate) inhibitor that has shown to reduce cell growth and/or induce cell death in solid tumors and hematological malignancies.. Konopleva:Novartis: Research Funding; AbbVie: Research Funding; Stemline: Research Funding; Calithera: Research Funding; Threshold: Research Funding.

On the role of oxygen in dehydrogenase reactions using tetrazolium salts

1988 ◽  
Vol 20 (10) ◽  
pp. 587-593 ◽  
Author(s):  
Cornelis J. F. Van Noorden
Keyword(s):  
Tetrazolium Salts

scholarly journals Characterisation of multi-metal resistant Serratia sp. GP01 for treatment of effluent from fertilizer industries

2021 ◽  
Author(s):  
Hrudananda Sahoo ◽  
Sushama Kumari ◽  
Darpa Saurav Jyethi ◽  
Umesh Chandra Naik
Keyword(s):  
Heavy Metals ◽  
Antioxidant Enzymes ◽  
Health Hazard ◽  
Metal Resistance ◽  
Bacterial Strains ◽  
16S Rdna Sequence ◽  
Reductase Gene ◽  
Enzymatic Reduction ◽  
Mapping Analysis

Abstract The effluent generated from fertilizer plants in Paradeep in the coast of the Bay of Bengal is the major pollutant causing health hazard in the vicinity of the area with respect to plants, animals and microbes. Samples of effluent were found to contain heavy metals (mg L-1): Cr (100), Ni (36.975), Mn (68.673), Pb (20.133), Cu (74.44), Zn (176.716), Hg (5.358) and As (24.287) as analyzed by XRF. Indigenous bacterial strains were screened for chromate and multi-metal resistance to remediate the toxic pollutants. The isolated strain G1 was identified as Serratia sp. through 16S-rDNA sequence homology. Potent strain Serratia sp. GP01 treated with 100 mg L-1 of K2Cr2O7 has shown the efficacy of reducing 69.05 mg L-1 of Cr over 48 h of incubation. Further, presence of chromate reductase gene (ChR) in Serratia sp. confirmed the enzymatic reduction of Cr (VI). SEM-EDX and SEM mapping analysis revealed substantial biosorption of Cr and other heavy metals present in effluent by Serratia sp. GP01. Antioxidant enzymes such as catalase (72.15 U mL-1), SOD (57.14 U mL-1) and peroxidase (62.49 U mL-1) were found to be higher as compared to the control condition. FTIR study also revealed the role of N-H, O-H, C = C, C-H, C-O, C-N, and C = O functional groups of the cell surface of Serratia sp. treated with K2Cr2O7 and effluent from the fertilizer industry. Isolated strain Serratia sp. could be used for the detoxification of Cr (VI) and other heavy metals in fertilizer plant effluent.

The role of oxygen in the reduction of tetrazolium salts with nadh mediated by 5-methyl phenazonium methyl sulfate. An EPR and voltammetric study

1993 ◽  
Vol 19 (7) ◽  
pp. 643-656 ◽  
Author(s):  
P. Carloni ◽  
L. Greci ◽  
E. Maurelli ◽  
P. Stipa ◽  
M. Wozniak ◽  
...  
Keyword(s):  
Methyl Sulfate ◽  
Tetrazolium Salts ◽  
Voltammetric Study

On the role of N -7-mercaptoheptanoyl-O -phospho-L-threonine (component B) in the enzymatic reduction of methyl-coenzyme M to methane

FEBS Letters ◽  
1987 ◽  
Vol 220 (2) ◽  
pp. 358-362 ◽  
Author(s):  
J. Ellermann ◽  
A. Kobelt ◽  
A. Pfaltz ◽  
R.K. Thauer
Keyword(s):  
Coenzyme M ◽  
Enzymatic Reduction
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