Enzymic denitrosation of 1,3-dimethyl-2-cyano-1-nitrosoguanidine in rat liver cytosol and the fate of the immediate product S-nitrosoglutathione

Jensen, David E.; Belka, George K.

doi:10.1016/s0006-2952(96)00860-x

Cited by 8 publications

(8 citation statements)

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“…It is unclear whether the reduction of reaction intermediates by GSH is also enzyme catalysed. Consistent with these properties of the rat liver enzyme, mammalian cells produce variable, but low, amounts of nitrite, but neglible nitrate, when exposed to GSNO [13,14] or compounds which gave rise to GSNO [15]. Paradoxically, glutathione sulphinamide could also be detected in cell-free extracts which had been exposed to GSNO and NADH, but intact cells were found not to accumulate glutathione sulphinamide when exposed to GSNO [11,16].…”

Section: Introductionmentioning

confidence: 63%

“…An enzyme which catalysed the reduction of nitrosothiols was first discovered during studies on the metabolism of a xenobiotic. These studies established GSNO as an important intermediate in the catabolism of 1,3-dimethyl-2-cyano-1-nitrosoguanidine [15] and identified GSNO reductase activity as an inherent property of the alcohol dehydrogenase class III isoenzyme [11], which also catalysed a GSH-dependent oxidation of formaldehyde to Sformylglutathione. Depending on the presence of GSH, however, GSNO reductase was found to produce different products [11].…”

Section: Resultsmentioning

confidence: 99%

“…GSNO, GSSG and nitrate were analysed by anion exchange chromatography essentially as described previously [15]. After centrifugation to remove bacteria, samples of the culture medium were applied to a 250 mm × 4.6 mm Partisil 10 SAX column and eluted at a flow rate of 1.5 ml/min as follows: solvent A for 2 min, followed by a linear gradient of 0-50 % solvent B for 10 min, a linear gradient of 50-100 % solvent B for 3 min, 100 % solvent B for 2 min, followed by a return to 0 % solvent B (solvent A: 7 mM H 3 PO 4 ; solvent B: 300 mM H 3 PO 4 adjusted to pH 2.0 with KOH).…”

Section: Analysis Of Gsno and The Products Of Its Dissimilationmentioning

confidence: 99%

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The metabolism of nitrosothiols in the mycobacteria: identification and characterization of S-nitrosomycothiol reductase

Vogt

Steenkamp

Zheng

et al. 2003

Biochemical Journal

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When grown in culture Mycobacterium smegmatis metabolized S-nitrosoglutathione to oxidized glutathione and nitrate, which suggested a possible involvement of an S-nitrosothiol reductase and mycobacterial haemoglobin. The mycothiol-dependent formaldehyde dehydrogenase from M. smegmatis was purified by a combination of Ni2+-IMAC (immobilized metal ion affinity chromatography), hydrophobic interaction, anion-exchange and affinity chromatography. The enzyme had a subunit molecular mass of 38263 kDa. Steady-state kinetic studies indicated that the enzyme catalyses the NAD+-dependent conversion of S-hydroxymethylmycothiol into formic acid and mycothiol by a rapid-equilibrium ordered mechanism. The enzyme also catalysed an NADH-dependent decomposition of S-nitrosomycothiol (MSNO) by a sequential mechanism and with an equimolar stoichiometry of NADH:MSNO, which indicated that the enzyme reduces the nitroso group to the oxidation level of nitroxyl. Vmax for the MSNO reductase reaction indicated a turnover per subunit of approx. 116700 min(-1), which was 76-fold faster than the formaldehyde dehydrogenase activity. A gene, Rv2259, annotated as a class III alcohol dehydrogenase in the Mycobacterium tuberculosis genome was cloned and expressed in M. smegmatis as the C-terminally His6-tagged product. The purified recombinant enzyme from M. tuberculosis also catalysed both activities. M. smegmatis S-nitrosomycothiol reductase converted MSNO into the N -hydroxysulphenamide, which readily rearranged to mycothiolsulphinamide. In the presence of MSNO reductase, M. tuberculosis HbN (haemoglobin N) was converted with low efficiency into metHbN [HbN(Fe3+)] and this conversion was dependent on turnover of MSNO reductase. These observations suggest a possible route in vivo for the dissimilation of S-nitrosoglutathione.

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Section: Introductionmentioning

confidence: 63%

Section: Resultsmentioning

confidence: 99%

Section: Analysis Of Gsno and The Products Of Its Dissimilationmentioning

confidence: 99%

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The metabolism of nitrosothiols in the mycobacteria: identification and characterization of S-nitrosomycothiol reductase

Vogt

Steenkamp

Zheng

et al. 2003

Biochemical Journal

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“…Addition of millimolar concentrations of NADPH to cytosol fractions of rat liver has been reported to increase the rate of GSNO disappearance [38]. NADPH could indeed be utilized as coenzyme, but with three orders of magnitude lower efficiency, primarily due to higher K m as compared to NADH (Table 2).…”

Section: Discussionmentioning

confidence: 99%

Reduction of S‐nitrosoglutathione by human alcohol dehydrogenase 3 is an irreversible reaction as analysed by electrospray mass spectrometry

Hedberg

Griffiths

Nilsson

et al. 2003

European Journal of Biochemistry

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Human alcohol dehydrogenase 3/glutathione-dependent formaldehyde dehydrogenase was shown to rapidly and irreversibly catalyse the reductive breakdown of S-nitrosoglutathione. The steady-state kinetics of S-nitrosoglutathione reduction was studied for the wild-type and two mutated forms of human alcohol dehydrogenase 3, mutations that have previously been shown to affect the oxidative efficiency for the substrate S-hydroxymethylglutathione. Wild-type enzyme readily reduces S-nitrosoglutathione with a k cat /K m approximately twice the k cat /K m for S-hydroxymethylglutathione oxidation, resulting in the highest catalytic efficiency yet identified for a human alcohol dehydrogenase. In a similar manner as for S-hydroxymethylglutathione oxidation, the catalytic efficiency of S-nitrosoglutathione reduction was significantly decreased by replacement of Arg115 by Ser or Lys, supporting similar substrate binding. NADH was by far a better coenzyme than NADPH, something that previously has been suggested to prevent reductive reactions catalysed by alcohol dehydrogenases through the low cytolsolic NADH/NAD + ratio. However, the major products of S-nitrosoglutathione reduction were identified by electrospray tandem mass spectrometry as glutathione sulfinamide and oxidized glutathione neither of which, in their purified form, served as substrate or inhibitor for the enzyme. Hence, the reaction products are not substrates for alcohol dehydrogenase 3 and the overall reaction is therefore irreversible. We propose that alcohol dehydrogenase 3 catalysed S-nitrosoglutathione reduction is of physiological relevance in the metabolism of NO in humans.

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“…After a temporary warm ischemia (Pringle), rGSH L was reduced by 14%‐69% with a concomitant 4‐fold increase of GSSG L 51, 52. However, unaltered53 or even a slight decrease of GSSG L was also found,54 whereas activity in GSH‐associated enzyme systems largely increased 55, 56. Although we expected warm ischemia in NHBD to result in a more severe, depletive form of oxidative stress,57 the fact that the decrease in erythrocyte and liver GSH, at the end of ATx (60‐90 minutes) was comparable to controls, was surprising.…”

Section: Discussionmentioning

confidence: 99%

Reduced glutathione in the liver as a potential viability marker in non-heart-beating donors

Golling¹,

Kellner

Fonouni³

et al. 2008

Liver Transpl

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Although the use of non-heart-beating donors (NHBD) is the oldest type of organ transplantation, the results were and still are disappointing. To consider using a liver from NHBD, it is of importance to assess the graft viability. Our aim was to assess the role of reduced liver glutathione (rGSHL) as a potential predictive marker of liver function before transplantation. Autotransplanted livers were subjected to 0, 60, and 90 minutes of ischemia in 20 pigs. We analyzed systemic cardiocirculatory parameters, bowel ischemia by endotoxin, endotoxin-neutralizing capacity, oxidative stress, hepatic perfusion parameters, liver enzymes, local bowel ischemia, and liver oxidative stress (rGSHL and oxidized glutathione in the liver). Autotransplantation was comparable to donor explantation/recipient transplantation with respect to systemic and hepatic parameters. Liver ischemia for 0, 60, and 90 minutes resulted in survival in 100% (NHBD-0), 71% (NHBD-60), and 57% (NHBD-90) of animals. Of all parameters, only hepatic microperfusion, pHi of the sigmoid colon, and bowel ischemia by endotoxin in the NHBD-90 group showed significant changes compared to NHBD-60 and control animals. Although systemic endotoxin-neutralizing capacity and total glutathione in erythrocytes levels were mainly influenced by cold perfusion, hepatic oxidative stress increased with ischemia time. The cut-off value of 11.5 ng/mmol of rGSHL could distinguish survivors from nonsurvivors, independent of the ischemia time. In conclusion, rGSHL has the potential of becoming an important viability marker, as it could predict survival in autotransplantation NHBD model regardless of the ischemia time. Further investigation to declare reasons for differing rGSHL levels within the liver is required. Liver Transpl 14: [1637][1638][1639][1640][1641][1642][1643][1644][1645][1646][1647] 2008. © 2008 AASLD. Received March 13, 2008; accepted June 5, 2008.The use of non-heart-beating donors (NHBD) is the oldest type of solid organ transplantation. With respect to the liver, an important organ, results have been disappointing. Primary liver nonfunction (PNF) is dependent on the donor being in a stable/controlled or unstable/uncontrolled stage. Transplantation from uncontrolled NHBD results in 50%-75% of livers having PNF and a 6-month graft survival of between 17% and 50%.1,2 In adult controlled NHBD, 1-year and 3-year liver graft survival improved up to 69% and 59%, respectively, 3,4 whereas pediatric graft survival from controlled NHBD can now reach 1-year and 5-year graft survival rates of 89% and 79%, respectively.5 Despite this progress, wider application of such livers is under Abbreviations: AF, aortic flow; ALT, alanine aminotransferase; AST, aspartate aminotransferase; ATx, autotransplantation; CVP, central venous pressure; ENC, endotoxin-neutralizing capacity; GSH, glutathione; GSSG, oxidized glutathione; GSSG E , oxidized glutathione in erythrocytes; GSSG L , oxidized glutathione in the liver; HAF, hepatic artery flow; i.v., intravenously; IVC, inferior vena ca...

show abstract

Enzymic denitrosation of 1,3-dimethyl-2-cyano-1-nitrosoguanidine in rat liver cytosol and the fate of the immediate product S-nitrosoglutathione

Cited by 8 publications

References 50 publications

The metabolism of nitrosothiols in the mycobacteria: identification and characterization of S-nitrosomycothiol reductase

The metabolism of nitrosothiols in the mycobacteria: identification and characterization of S-nitrosomycothiol reductase

Reduction of S‐nitrosoglutathione by human alcohol dehydrogenase 3 is an irreversible reaction as analysed by electrospray mass spectrometry

Reduced glutathione in the liver as a potential viability marker in non-heart-beating donors

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