Limits...
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 of synthetic trisulfanes ATSP and ATSEE, respectively, with 200 µM GSNO in the presence of 800 µM Cys. The traces for DATS and DPTS are shown for comparison.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5384177&req=5

antioxidants-06-00014-f006: Kinetic traces of the interactions of 200 µM of synthetic trisulfanes ATSP and ATSEE, respectively, with 200 µM GSNO in the presence of 800 µM Cys. The traces for DATS and DPTS are shown for comparison.

Mentions: In line with these observations and our hypothesis, i.e., that reduction releases H2S from organic polysulfanes and therefore explains their ability to decompose GSNO, a strong interaction of ATSP and ATSEE with GSNO in the presence of cysteine or GSH has also been noticed. Figure 6 illustrates this superior behaviour of the synthetic trisulfanes. ATSEE, in particular, readily and rapidly decomposes GSNO once “activated” via reduction with cysteine. It also causes the temporary appearance of the characteristic yellow colour of SSNO−, followed by a rapid build-up of disulfide species. ATSP is slightly less active, in line with its somewhat lesser ability to liberate H2S upon reduction (see Figure 5).


Inorganic Reactive Sulfur-Nitrogen Species: Intricate Release Mechanisms or Cacophony in Yellow, Blue and Red?
Kinetic traces of the interactions of 200 µM of synthetic trisulfanes ATSP and ATSEE, respectively, with 200 µM GSNO in the presence of 800 µM Cys. The traces for DATS and DPTS are shown for comparison.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

antioxidants-06-00014-f006: Kinetic traces of the interactions of 200 µM of synthetic trisulfanes ATSP and ATSEE, respectively, with 200 µM GSNO in the presence of 800 µM Cys. The traces for DATS and DPTS are shown for comparison.
Mentions: In line with these observations and our hypothesis, i.e., that reduction releases H2S from organic polysulfanes and therefore explains their ability to decompose GSNO, a strong interaction of ATSP and ATSEE with GSNO in the presence of cysteine or GSH has also been noticed. Figure 6 illustrates this superior behaviour of the synthetic trisulfanes. ATSEE, in particular, readily and rapidly decomposes GSNO once “activated” via reduction with cysteine. It also causes the temporary appearance of the characteristic yellow colour of SSNO−, followed by a rapid build-up of disulfide species. ATSP is slightly less active, in line with its somewhat lesser ability to liberate H2S upon reduction (see Figure 5).

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