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Inorganic Reactive Sulfur-Nitrogen Species: Intricate Release Mechanisms or Cacophony in Yellow, Blue and Red?

View Article: PubMed Central - PubMed

ABSTRACT

Since the heydays of Reactive Sulfur Species (RSS) research during the first decade of the Millennium, numerous sulfur species involved in cellular regulation and signalling have been discovered. Yet despite the general predominance of organic species in organisms, recent years have also seen the emergence of inorganic reactive sulfur species, ranging from inorganic polysulfides (HSx−/Sx2−) to thionitrous acid (HSNO) and nitrosopersulfide (SSNO−). These inorganic species engage in a complex interplay of reactions in vitro and possibly also in vivo. Employing a combination of spectrophotometry and sulfide assays, we have investigated the role of polysulfanes from garlic during the release of nitric oxide (•NO) from S-nitrosoglutathione (GSNO) in the absence and presence of thiol reducing agents. Our studies reveal a distinct enhancement of GSNO decomposition by compounds such as diallyltrisulfane, which is most pronounced in the presence of cysteine and glutathione and presumably proceeds via the initial release of an inorganic mono- or polysulfides, i.e., hydrogen sulfide (H2S) or HSx−, from the organic polysulfane. Albeit being of a preliminary nature, our spectrophotometric data also reveals a complicated underlying mechanism which appears to involve transient species such as SSNO−. Eventually, more in depth studies are required to further explore the underlying chemistry and wider biological and nutritional implications of this interplay between edible garlic compounds, reductive activation, inorganic polysulfides and their interplay with •NO storage and release.

No MeSH data available.


Related in: MedlinePlus

Kinetic traces of the interactions of 200 µM DATS with 200 µM GSNO in the absence and presence of various concentrations of cysteine (Cys, left, A) and reduced glutathione (GSH, right, B) monitored at three characteristic wavelengths by UV/VIS spectrophotometry (334 nm—GSNO decomposition, 412 nm—formation of SSNO−, 270 nm—formation of hydroper-/polysulfides). The maximum rate of GSNO decomposition was achieved at concentrations of 800 or 1600 µM Cys/GSH.
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antioxidants-06-00014-f003: Kinetic traces of the interactions of 200 µM DATS with 200 µM GSNO in the absence and presence of various concentrations of cysteine (Cys, left, A) and reduced glutathione (GSH, right, B) monitored at three characteristic wavelengths by UV/VIS spectrophotometry (334 nm—GSNO decomposition, 412 nm—formation of SSNO−, 270 nm—formation of hydroper-/polysulfides). The maximum rate of GSNO decomposition was achieved at concentrations of 800 or 1600 µM Cys/GSH.

Mentions: Figure 3 exhibits the representative example of DATS which indeed is unable to decompose GSNO single-handedly on its own. Interestingly, when a thiol-based reducing agent, such as Cys or GSH, is added, the system becomes “activated” in a concentration dependent manner and GSNO is decomposed rapidly, i.e., within 30 min, as can be observed by a sharp decline in the absorbance at 334 nm (ʎmax(GSNO)).


Inorganic Reactive Sulfur-Nitrogen Species: Intricate Release Mechanisms or Cacophony in Yellow, Blue and Red?
Kinetic traces of the interactions of 200 µM DATS with 200 µM GSNO in the absence and presence of various concentrations of cysteine (Cys, left, A) and reduced glutathione (GSH, right, B) monitored at three characteristic wavelengths by UV/VIS spectrophotometry (334 nm—GSNO decomposition, 412 nm—formation of SSNO−, 270 nm—formation of hydroper-/polysulfides). The maximum rate of GSNO decomposition was achieved at concentrations of 800 or 1600 µM Cys/GSH.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5384177&req=5

antioxidants-06-00014-f003: Kinetic traces of the interactions of 200 µM DATS with 200 µM GSNO in the absence and presence of various concentrations of cysteine (Cys, left, A) and reduced glutathione (GSH, right, B) monitored at three characteristic wavelengths by UV/VIS spectrophotometry (334 nm—GSNO decomposition, 412 nm—formation of SSNO−, 270 nm—formation of hydroper-/polysulfides). The maximum rate of GSNO decomposition was achieved at concentrations of 800 or 1600 µM Cys/GSH.
Mentions: Figure 3 exhibits the representative example of DATS which indeed is unable to decompose GSNO single-handedly on its own. Interestingly, when a thiol-based reducing agent, such as Cys or GSH, is added, the system becomes “activated” in a concentration dependent manner and GSNO is decomposed rapidly, i.e., within 30 min, as can be observed by a sharp decline in the absorbance at 334 nm (ʎmax(GSNO)).

View Article: PubMed Central - PubMed

ABSTRACT

Since the heydays of Reactive Sulfur Species (RSS) research during the first decade of the Millennium, numerous sulfur species involved in cellular regulation and signalling have been discovered. Yet despite the general predominance of organic species in organisms, recent years have also seen the emergence of inorganic reactive sulfur species, ranging from inorganic polysulfides (HSx−/Sx2−) to thionitrous acid (HSNO) and nitrosopersulfide (SSNO−). These inorganic species engage in a complex interplay of reactions in vitro and possibly also in vivo. Employing a combination of spectrophotometry and sulfide assays, we have investigated the role of polysulfanes from garlic during the release of nitric oxide (•NO) from S-nitrosoglutathione (GSNO) in the absence and presence of thiol reducing agents. Our studies reveal a distinct enhancement of GSNO decomposition by compounds such as diallyltrisulfane, which is most pronounced in the presence of cysteine and glutathione and presumably proceeds via the initial release of an inorganic mono- or polysulfides, i.e., hydrogen sulfide (H2S) or HSx−, from the organic polysulfane. Albeit being of a preliminary nature, our spectrophotometric data also reveals a complicated underlying mechanism which appears to involve transient species such as SSNO−. Eventually, more in depth studies are required to further explore the underlying chemistry and wider biological and nutritional implications of this interplay between edible garlic compounds, reductive activation, inorganic polysulfides and their interplay with •NO storage and release.

No MeSH data available.


Related in: MedlinePlus