The reaction of alloxan with glutathione and protein

Resnik, Robert A.; Wolff, Ann R.

doi:10.1016/0003-9861(56)90239-9

Cited by 15 publications

(2 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This compound absorbs light within the range of 295 to 320 nm. It might be identical with the so called Lazarows compound [9], a chemical substance supposedly formed by glutathione and alloxan [9,18]. Assuming this is correct, than the adduct of glutathione and alloxan would partially decrease the formation of dialuric acid, and therefore may reduce ROS generation.…”

Section: Discussionmentioning

confidence: 99%

Simultaneous Quantitative Determination of Alloxan, GSH and GSSG by HPLC. Estimation of the Frequency of Redox Cycling Between Alloxan and Dialuric Acid

Weinandy¹,

Peschke²,

Peschke³

2001

Horm Metab Res

View full text Add to dashboard Cite

This in vitro study compares the frequency of redox cycling between alloxan and dialuric acid at different initial ratios of glutathione and alloxan. Alloxan oxidizes GSH to GSSG. The rate of GSH oxidation at a given initial GSH concentration of 2.0 mmol/L depends on the initial concentration of alloxan added. The higher the concentration of alloxan in relation to the initial concentration of GSH, the faster GSH oxidation proceeds, as well as oxygen consumption, and therefore, formation of reactive oxygen species. The highest rates of GSH oxidation, i.e. GSSG formation, were found at concentration ratios of between 2.0 mmol/L GSH and 0.2 and 0.04 mmol/L alloxan, respectively. Because 0.04 mmol/L alloxan oxidizes 2.0 mmol/L GSH completely, a frequency of at least 25 cycles between alloxan and dialuric acid within 3 hours can be assumed. During each redox cycle, two molecules of GSH are oxidized to one molecule of GSSG, and during each cycle one molecule of oxygen is reduced simultaneously to one molecule of hydrogen peroxide. In total, therefore, one molecule of alloxan oxidizes at least 50 molecules of GSH and forms about 25 molecules of hydrogen peroxide.

show abstract

Section: Discussionmentioning

confidence: 99%

Simultaneous Quantitative Determination of Alloxan, GSH and GSSG by HPLC. Estimation of the Frequency of Redox Cycling Between Alloxan and Dialuric Acid

Weinandy¹,

Peschke²,

Peschke³

2001

Horm Metab Res

View full text Add to dashboard Cite

show abstract

“…Alloxan (2,4,5,6−(1H,3H)−pyrimidinetetrone) is a polar, water−sol− uble oxidant that spontaneously decays within minutes into al− loxanic acid at neutral pH and in the absence of reductants [1,2]. This decomposition is accelerated by hydroxide anions (OH ± ), but does not appear to be influenced by oxygen.…”

Section: Introductionmentioning

confidence: 99%

Influence of Oxygen Concentration on Redox Cycling of Alloxan and Dialuric Acid

Brömme¹,

Weinandy²,

Peschke³

2005

Horm Metab Res

View full text Add to dashboard Cite

Alloxan, a chemical diabetogen, decays in the absence of reductants into alloxanic acid. In the presence of glutathione, it is reduced via the alloxan radical into dialuric acid, which autoxidizes back to alloxan. During this redox cycling process, reactive oxygen species are formed that destroy beta-cells in islets of Langerhans. Previous experiments were conducted with oxygen concentrations about ten times as high as within cells. The aim of our in vitro study was to evaluate the impact of different oxygen concentrations (0, 25, 250 micromol/l) at a given initial ratio of glutathione and alloxan on this redox cycling. Reduction of alloxan, oxidation of glutathione, and the formation of glutathiol (GSSG) were continuously recorded by HPLC for 90 minutes at 25 degrees C in air, calibration gas, or argon. In the absence of reductants, alloxan irreversibly decomposed into alloxanic acid regardless of oxygen presence. When the reaction system contained glutathione, decomposition was significantly retarded and therefore influenced by oxygen. In argon, decay could not be observed due to its reduction and the absence of oxygen. Increasing oxygen concentration enabled a redox cycling and therefore an ongoing decay. The highest decomposition along with the highest consumption of glutathione occurred at 250 micromol/l oxygen. The lower the oxygen, the more dialuric acid could be detected. After calculation, about 33 redox cycles per hour generates an amount of reactive oxygen species sufficient to damage pancreatic beta cells and induce insulin deficiency.

show abstract

Spectrophotometric Determination of Dissociation Constants of Thiovioluric Acid and the Stability Constant of its Fe(II) Complex

Singh

Ghosh

1981

J Chinese Chemical Soc

View full text Add to dashboard Cite

Spectrophotometric studies of Fe(II)‐thiovioluric acid system indicates the presence of a 1:2 complex in the pH range 4.0–6.5. The apparent equilibrium constant (K′1) has been determined by general absorbance‐extinction concentration scheme. The first and second dissociation constants of the acid have been studied at an ionic strength of 0.1 M while the third dissociation constant has been determined at I = 1 M. The effects of sudden pH change and buffer compositions on the dissociations have also been investigated. The stability constant of the complex has been calculated from the apparent equilibrium constant at ionic strength of 0.1 M. The stability constant works out to be 15.67 at pH 5.5.

show abstract

The reaction of alloxan with glutathione and protein

Cited by 15 publications

References 19 publications

Simultaneous Quantitative Determination of Alloxan, GSH and GSSG by HPLC. Estimation of the Frequency of Redox Cycling Between Alloxan and Dialuric Acid

Simultaneous Quantitative Determination of Alloxan, GSH and GSSG by HPLC. Estimation of the Frequency of Redox Cycling Between Alloxan and Dialuric Acid

Influence of Oxygen Concentration on Redox Cycling of Alloxan and Dialuric Acid

Spectrophotometric Determination of Dissociation Constants of Thiovioluric Acid and the Stability Constant of its Fe(II) Complex

Contact Info

Product

Resources

About