Oxidation of formate by mycobacteria of the Scrofulaceum group

1978 ◽  
Vol 24 (12) ◽  
pp. 1548-1552
Author(s):  
M. Ishaque ◽  
S. J. Kim ◽  
L. Kato

Intact cells obtained from Mycobacterium scrofulaceum as well as from mycobacterial strains M.A6 and M.R56 isolated respectively from leprous tissues of armadillo and rat leproma and grown with glycerol as the oxidizable substrate catalyzed complete oxidation of formate. The stoichiometry of formate oxidase system yielded a value of 2 mol of CO2 produced per mole of O2 or per 2 moles of formate consumed. Cell-free preparations from these three strains of mycobacteria contained formate dehydrogenase which was associated exclusively in the particulate fraction. Formate oxidation was markedly stimulated by small amounts of selenite and molybdate added together. Formate-reduced minus oxidized difference spectra disclosed cytochromes of the b type while spectral evidence did not suggest the existence of cytochromes a or c components. The effect of 2-N-heptyl-4-hydroxyquinoline-N-oxide on the redox state of cytochromes indicated that formate oxidation was mediated by cytochrome b with absorption maximum of 556 nm and not of 562 nm.

1983 ◽  
Vol 210 (3) ◽  
pp. 721-725 ◽  
Author(s):  
R I Scott ◽  
D Lloyd

1. Room-temperature CO-reduced minus reduced difference spectra of intact cells of Acanthamoeba castellanii show the presence of CO-reacting haemoproteins in cells from the early-exponential, late-exponential and stationary phases of growth. 2. The relative rates of reaction with CO of the two haemoproteins differ; that of cytochrome a/a3 with CO is complete within 1 min of bubbling with CO, whereas that of cytochrome b takes longer than 90 min. 3. Photochemical action spectra reveal cytochrome a/a3 as the predominant haemoprotein oxidase at all stages of growth. 4. It is concluded that the alternative oxidases known to be present in these organisms are not cytochromes.


1987 ◽  
Vol 7 (3) ◽  
pp. 193-199 ◽  
Author(s):  
Steven W. Edwards ◽  
David Lloyd

Room temperature, CO-difference spectra of intact rat polymorphonuclear leucocytes (neutrophils) revealed the presence of a number of CO-binding haemoproteins. Absorption maxima at 413, 540 and 570 nm were attributed to the CO-complex of cytochrome b-245 whereas an absorption maximum at 595 nm was assigned to the contribution from a myeloperoxidase complex, since an identical absorption maximum was observed in CO-difference spectra of purified myeloperoxidase in the presence of H2O2. Photochemical action spectra for the relief of CO-inhibited O2 uptake revealed contributions from both cytochrome b-245 and myeloperoxidase. The potential of these two O2- and CO-binding haemoproteins to function as oxidases during the respiratory burst is discussed.


2019 ◽  
Vol 35 (6) ◽  
pp. 21-29
Author(s):  
T.E. Leonova ◽  
T.E. Shustikova ◽  
T.V. Gerasimova ◽  
Т.А. Ivankova ◽  
K.V. Sidorenko Sidorenko ◽  
...  

Thepsefdh_D221Q gene coding for a mutant formate dehydrogenase (PseFDG_D221Q) from Pseudomonas, which catalyzes the formate oxidation with the simultaneous formation of NADPH, has been expressed in the cells of lysine-producing Corynebacterium glutamicum strains. The psefdh_D221Q gene was introduced into С. glutamicum strains as part of an autonomous plasmid or was integrated into the chromosome with simultaneous inactivation of host formate dehydrogenase genes. It was shown that the С. glutamicum strains with NADP+ -dependent formate dehydrogenase have an increased level of L-lysine synthesis in the presence of formate, if their own formate dehydrogenase is inactivated. L-lysine, formate dehydrogenase, NADPH, Corynebacterium glutamicum The work was carried out using the equipment of the Multipurpose Scientific This work was carried out on the equipment of the Multipurpose Scientific Installation of «All-Russian Collection of Industrial Microorganisms», National Bio-Resource Center, NRC «Kurchatov Institute»- GosNIIgenetika. This work was financially supported by the Ministry of Education and Science of Russia (Unique Project Identifier - RFMEFI61017X0011).


Genetics ◽  
1990 ◽  
Vol 125 (4) ◽  
pp. 691-702 ◽  
Author(s):  
B L Berg ◽  
V Stewart

Abstract Formate oxidation coupled to nitrate reduction constitutes a major anaerobic respiratory pathway in Escherichia coli. This respiratory chain consists of formate dehydrogenase-N, quinone, and nitrate reductase. We have isolated a recombinant DNA clone that likely contains the structural genes, fdnGHI, for the three subunits of formate dehydrogenase-N. The fdnGHI clone produced proteins of 110, 32 and 20 kDa which correspond to the subunit sizes of purified formate dehydrogenase-N. Our analysis indicates that fdnGHI is organized as an operon. We mapped the fdn operon to 32 min on the E. coli genetic map, close to the genes for cryptic nitrate reductase (encoded by the narZ operon). Expression of phi(fdnG-lacZ) operon fusions was induced by anaerobiosis and nitrate. This induction required fnr+ and narL+, two regulatory genes whose products are also required for the anaerobic, nitrate-inducible activation of the nitrate reductase structural gene operon, narGHJI. We conclude that regulation of fdnGHI and narGHJI expression is mediated through common pathways.


1969 ◽  
Vol 115 (4) ◽  
pp. 609-619 ◽  
Author(s):  
R. L. Veech ◽  
L. V. Eggleston ◽  
H. A. Krebs

1. The concentrations of the oxidized and reduced substrates of the ‘malic’ enzyme (EC 1.1.1.40) and isocitrate dehydrogenase (EC 1.1.1.42) were measured in freeze-clamped rat livers. By assuming that the reactants of these dehydrogenase systems are at equilibrium in the cytoplasm the [free NADP+]/[free NADPH] ratio was calculated. The justification of the assumption is discussed. 2. The values of this ratio obtained under different nutritional conditions (well-fed, 48hr.-starved, fed with a low-carbohydrate diet, fed with a high-sucrose diet) were all of the same order of magnitude although characteristic changes occurred on varying the diet. The value of the ratio fell on starvation and on feeding with the low-carbohydrate diet and rose slightly on feeding with the high-sucrose diet. 3. The mean values of the ratio were calculated to be between 0·001 and 0·015, which is about 100000 times lower than the values of the cytoplasmic [free NAD+]/[free NADH] ratio. 4. The differences in the redox state of the two nicotinamide–adenine dinucleotide couples can be explained on a simple physicochemical basis. The differences are the result of equilibria that are determined by the equilibrium constants of a number of highly active readily reversible dehydrogenases and transaminases and the concentrations of the substrates and products of these enzymes. 5. The decisive feature is the fact that the NAD and NADP couples share substrates. This sharing provides a link between the redox states of the two couples. 6. The application of the method of calculation to data published by Kraupp, Adler-Kastner, Niessner & Plank (1967), Goldberg, Passonneau & Lowry (1966) and Kauffman, Brown, Passonneau & Lowry (1968) shows that the redox states of the NAD and NADP couples in cardiac-muscle cytoplasm and in mouse-brain cytoplasm are of the same order as those in rat liver. 7. The determination of the equilibrium constant at 38°, pH7·0 and I 0·25 (required for the calculation of the [free NADP+]/[free NADPH] ratio), gave a value of 3·44×10−2m for the ‘malic’ enzyme (with CO2 rather than HCO3− as the reactant) and a value of 1·98×10−2m−1 for glutathione reductase.


Endocrinology ◽  
2009 ◽  
Vol 150 (9) ◽  
pp. 4154-4162 ◽  
Author(s):  
Daniel P. Sherbet ◽  
Oleg L. Guryev ◽  
Mahboubeh Papari-Zareei ◽  
Dario Mizrachi ◽  
Siayareh Rambally ◽  
...  

Abstract Human 17β-hydroxysteroid dehydrogenase types 1 and 2 (17βHSD1 and 17βHSD2) regulate estrogen potency by catalyzing the interconversion of estrone (E1) and estradiol (E2) using nicotinamide adenine dinucleotide (phosphate) cofactors NAD(P)(H). In intact cells, 17βHSD1 and 17βHSD2 establish pseudo-equilibria favoring E1 reduction or E2 oxidation, respectively. The vulnerability of these equilibrium steroid distributions to mutations and to altered intracellular cofactor abundance and redox state, however, is not known. We demonstrate that the equilibrium E2/E1 ratio achieved by 17βHSD1 in intact HEK-293 cell lines is progressively reduced from 94:6 to 10:90 after mutagenesis of R38, which interacts with the 2′-phosphate of NADP(H), and by glucose deprivation, which lowers the NADPH/NADP+ ratio. The shift to E2 oxidation parallels changes in apparent Km values for purified 17βHSD1 proteins to favor NAD(H) over NADP(H). In contrast, mutagenesis of E116 (corresponding to R38 in 17βHSD1) and changes in intracellular cofactor ratios do not alter the greater than 90:10 E1/E2 ratio catalyzed by 17βHSD2, and these mutations lower the apparent Km of recombinant 17βHSD2 for NADP(H) only less than 3-fold. We conclude that the equilibrium E1/E2 ratio maintained by human 17βHSD1 in intact cells is governed by NADPH saturation, which is strongly dependent on both R38 and high intracellular NADPH/NADP+ ratios. In contrast, the preference of 17βHSD2 for E2 oxidation strongly resists alteration by genetic and metabolic manipulations. These findings suggest that additional structural features, beyond the lack of a specific arginine residue, disfavor NADPH binding and thus support E2 oxidation by 17βHSD2 in intact cells.


1969 ◽  
Vol 114 (4) ◽  
pp. 793-799 ◽  
Author(s):  
O. T. G. Jones

Illumination of chromatophore preparations from Rhodopseudomonas spheroides causes the oxidation of a cytochrome c and a slight oxidation of a cytochrome b with a maximum at 560nm. When illuminated in the presence of antimycin A the oxidation of cytochrome c was more pronounced and cytochrome b560 was reduced; the dark oxidation of cytochrome b560 was biphasic in the presence of succinate, but not in the presence of NADH, a less effective reductant. Split-beam spectroscopy showed that, in addition to the reduction of cytochrome b560, another pigment with maxima at 565 and 537nm. was reduced and was more rapidly oxidized in the dark than cytochrome b560. This pigment, tentatively identified as cytochrome b565, was also detected in spectra at 77°k, after brief illumination at room temperature; the maxima at 77°k were at 562 and 536nm. In the absence of antimycin A, light caused a transient reduction of cytochrome b565 and an oxidation of cytochrome b560. Dark oxidation of b565 was rapid, even in the presence of antimycin A and succinate. Difference spectra, at 77°k, of ascorbate-reduced minus succinate-reduced chromatophores or of anaerobic succinate-reduced minus aerobic succinate-reduced chromatophores suggested that two cytochromes c were present, with maxima at 547 and 549nm. When chromatophores frozen at 77°k were illuminated both these cytochromes c were oxidized, indicating a close association with the photochemical reaction centre. A scheme involving two reaction centres is proposed to explain these results.


1979 ◽  
Vol 184 (3) ◽  
pp. 555-563 ◽  
Author(s):  
R K Poole ◽  
D Lloyd ◽  
B Chance

1. Cytochrome alpha 3 in whole-cell suspensions of the fission yeast Schizosaccharomyces pombe reacted in the reduced form with CO to give a photodissociable CO complex with absorption maxima at 429, 543 and 591 nm in CO-liganded reduced-minus-reduced difference spectra. 2. Other CO-bound haemoproteins, cytochromes P-420 and P-450, were not photodissociated under the conditions employed. 3. Measurements of the rates of reassociation of CO with cytochrome alpha 3 after flash photolysis over the temperature range from −101 to −109 degrees C gave a value for Eact. of 28.6 kJ/mol. 4. Between −94 and −106 degrees C, O2 reacted with cytochrome oxidase in intact cells to give an oxygenated intermediate (compound A). 5. At −70 degrees C compound A was converted into a second spectrally distinct intermediate (compound B). 6. Electron transport, indicated by the oxidation of cytochromes alpha + alpha 3 and cytochrome c, did not occur until the temperature was raised to −50 degrees C. 7. At room temperature cytochfome oxidase was oxidized to 50% of its steady-state concentration by 0.35 microM-O2.


1960 ◽  
Vol 38 (1) ◽  
pp. 79-93 ◽  
Author(s):  
R. M. Hochster ◽  
C. G. Nozzolillo

Intact cells and cell-free extracts of the phytopathogenic organism Xanthomonas phaseoli have been shown to contain flavoprotein and the respiratory carriers: cytochrome b1, cytochrome a1, and cytochrome a2. The reduced forms of these respiratory pigments are produced upon addition to a clear extract of substrate amounts of DPNH.The highly active DPNH oxidase system in extracts of this organism has been studied as to requirements for inorganic ions, optimum pH, product formation, distribution, and solubilization. Carbon monoxide inhibits the terminal oxidation system; this effect is reversed by bright light.An inhibitor study has shown members of the phenothiazine family of compounds to be most effective, followed by amytal, cyanide, BAL, atabrine, and pCMB. The most notable of the substances which did not inhibit were antimycin A, one of the quinoline-N-oxides, and azide.The possibility exists that H2O2may also be formed during the oxidation of DPNH although clear-cut evidence for its presence was difficult to obtain. X. phaseoli extracts do not contain a DPNH peroxidase. They exhibit, however, some DPNH – cytochrome c reductase activity which is believed to be quite independent of the DPNH oxidase system. The extracts are devoid of cytochrome c oxidase activity although they contain a respiratory system which readily oxidizes p-phenylenediamine.


1981 ◽  
Vol 59 (2) ◽  
pp. 137-144 ◽  
Author(s):  
Tsanyen Yang

The multiple cytochrome components in the electron transport particle of Azotobacter vinelandii were resolved and their oxidation–reduction midpoint potentials were determined by a simultaneous potentiometric and absorption measurements under anaerobic condition with or without CO. The midpoints of the individual cytochrome component corresponding to the membrane-bound types were also determined in the solubilized fractions prepared by a differential detergent solubilization of the membrane particles of A. vinelandii. Two cytochromes of b type, one with an absorption maximum measured at 559 nm and another at 561 nm in the membrane particle, were resolved and their Em, 7.4 values determined to be −30 mV and +122 mV, respectively. Cytochrome b559 reacted with CO readily in both membrane-bound and solubilized forms, however, cytochrome b561 was inert to CO treatment. Only one cytochrome of c type (c4) measured at 575–551 nm was resolved, its midpoint potential at pH 7.4 was +322 mV in the membrane-bound form and +278 mV in the solubilized form. This c-type cytochrome had no CO reactivity. Cytochrome d, a CO-reactive component, had a midpoint of +270 mV in the membrane fraction. The midpoint of cytochrome a1 in its membrane-bound form could not be measured accurately because of its low concentration. However, in the solubilized preparations, cytochrome a1 apparently had a red shift with an absorption maximum at 613 nm, with an estimated Em, 7.4 of −45 mV, while cytochrome d was no longer detected, possibly because of denaturation.


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