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Is aldehyde dehydrogenase inhibited by sulfur compounds? In vitro and in vivo studies

100%

Iciek M., Górny M., Bilska-Wilkosz A., Kowalczyk-Pachel D.

Acta Biochimica Polonica

2018

vol. 65

issue 1

125-132

Aldehyde dehydrogenase (ALDH) catalyzes the critical step of ethanol metabolism, i.e. transformation of toxic acetaldehyde to acetic acid. It is a redox sensitive protein with the key Cys in its active site. Recently, it has been documented that activity of some proteins can be modified by sulfur-containing molecules called reactive sulfur species leading to the formation of hydro- persulfides. The aim of the present study was to examine whether ALDH activity can be modified in this way. Studies were performed in vitro using yeast ALDH and various reactive sulfur species, including Na2S, GSSH, K2Sx, Na2S2O3, and garlic-derived allyl sulfides. The effect of garlic-derived trisulfide on ALDH activity was also studied in vivo in the rat liver. The obtained results clearly demonstrated that ALDH could be regulated by sulfur species which inhibited its enzymatic activity. The results also suggested that not H2S but polysulfides or hydropersulfides were the oxidizing species responsible for this modification. This process was easily reversible by reducing agents. After the treatment with polysulfides or hydropersulfides the level of protein-bound sulfur increased, while the activity of the enzyme dramatically decreased. Moreover, the study demonstrated that ALDH activity was inhibited in vivo in the rat liver after garlic-derived trisulfide administration. This is the first study reporting the regulation of ALDH activity by sulfane sulfur species and the results suggest that it leads to the inhibition of the enzyme.

Plasma levels of total, free and protein bound thiols as well as sulfane sulfur in different age groups of rats

88%

Iciek M., Chwatko G., Lorenc-Koci E., Bald E., Włodek L.

Acta Biochimica Polonica

2004

vol. 51

issue 3

815-824

The redox status of plasma thiols can be a diagnostic indicator of different pathological states. The aim of this study was to identify the age dependent changes in the plasma levels of total, free and protein bound glutathione, cysteine and homocysteine. The determination was conducted in plasma of three groups of rats: 1) young (3-month-old), 2) middle aged (19-month-old), and 3) old (31-month-old). Total levels of glutathione, cysteine and homocysteine and their respective free and protein-bound fractions decreased with age. The only exception was a rise in free homocysteine concentration in the middle group, which indicates a different pattern of transformations of this thiol in plasma. The drop in the level of protein-bound thiols suggests that the antioxidant capacity of plasma diminishes with age, which, consequently, leads to impaired protection of -SH groups through irreversible oxidation. The plasma sulfane sulfur level also declines with age, which means that aging is accompanied by inhibition of anaerobic sulfur metabolism.

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2 Acta Biochimica Polonica

1 2018

1 2004

2 Iciek M.

1 Bald E.

1 Bilska-Wilkosz A.

1 Chwatko G.

1 Górny M.

1 Kowalczyk-Pachel D.

1 Lorenc-Koci E.

1 Włodek L.

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Is aldehyde dehydrogenase inhibited by sulfur compounds? In vitro and in vivo studies

Plasma levels of total, free and protein bound thiols as well as sulfane sulfur in different age groups of rats