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Mario Fontana - One of the best experts on this subject based on the ideXlab platform.
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carbonate anion radical generated by the peroxidase activity of copper zinc superoxide dismutase scavenging of radical and protection of enzyme by Hypotaurine and cysteine sulfinic acid
Advances in Experimental Medicine and Biology, 2017Co-Authors: Alessia Baseggio Conrado, Simonetta Maina, H Moseley, Antonio Francioso, Luciana Mosca, Elisabetta Capuozzo, Mario FontanaAbstract:Copper-zinc superoxide dismutase (SOD) is considered one of the most important mammalian antioxidant defenses and plays a relevant role due to its main function in catalyzing the dismutation of superoxide anion to oxygen and hydrogen peroxide. However, interaction between SOD and H2O2 produced a strong copper-bound oxidant (Cu(II)•OH) that seems able to contrast the self-inactivation of the enzyme or oxidize other molecules through its peroxidase activity. The bicarbonate presence enhances the peroxidase activity and produces the carbonate anion radical (CO3•–). CO3 •– is a freely diffusible reactive species capable of oxidizing several molecules that are unwieldy to access into the reactive site of the enzyme. Cu(II)•OH oxidizes bicarbonate to the CO3•–, which spreads out of the binding site and oxidizes Hypotaurine and cysteine sulfinic acid to the respective sulfonates through an efficient reaction. These findings suggest a defense role for sulfinates against the damage caused by CO3 •– . The effect of Hypotaurine and cysteine sulfinic acid on the CO3•–-mediated oxidation of the peroxidase probe ABTS to ABTS cation radical (ABTS•+) has been studied. Both sulfinates are able to inhibit the oxidation of ABTS mediated by CO3•–. The effect of Hypotaurine and cysteine sulfinic acid against SOD inactivation by H2O2 (~42% protection of enzyme activity) has also been investigated. Interestingly, Hypotaurine and cysteine sulfinic acid partially avoid the H2O2-mediated SOD inactivation, suggesting that the two sulfinates may have access to the SOD reactive site and preserve it by reacting with the copper-bound oxidant. In this way Hypotaurine and cysteine sulfinic acid not only intercept CO3•– which could move out from the reactive site and cause oxidative damage, but also prevents the inactivation of SOD.
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reactivity of Hypotaurine and cysteine sulfinic acid toward carbonate radical anion and nitrogen dioxide as explored by the peroxidase activity of cu zn superoxide dismutase and by pulse radiolysis
Free Radical Research, 2014Co-Authors: Baseggio A Conrado, Laura Pecci, M Dangelantonio, A Torreggiani, Mario FontanaAbstract:AbstractHypotaurine and cysteine sulfinic acid are known to be readily oxidized to the respective sulfonates, taurine and cysteic acid, by several oxidative agents that may be present in biological systems. In this work, the relevance of both the carbonate anion and nitrogen dioxide radicals in the oxidation of Hypotaurine and cysteine sulfinic acid has been explored by the peroxidase activity of Cu,Zn superoxide dismutase (SOD) and by pulse radiolysis. The extent of sulfinate oxidation induced by the system SOD/H2O2 in the presence of bicarbonate (CO3•– generation), or nitrite (•NO2 generation) has been evaluated. Hypotaurine is efficiently oxidized by the carbonate radical anion generated by the peroxidase activity of Cu,Zn SOD. Pulse radiolysis studies have shown that the carbonate radical anion reacts with Hypotaurine more rapidly (k = 1.1 × 109 M−1s−1) than nitrogen dioxide (k = 1.6 × 107 M−1s−1). Regarding cysteine sulfinic acid, it is less reactive with the carbonate radical anion (k = 5.5 × 107 M−...
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the reactivity of Hypotaurine and cysteine sulfinic acid with peroxynitrite
Advances in Experimental Medicine and Biology, 2006Co-Authors: Mario Fontana, Silvestro Dupre, Laura PecciAbstract:The oxidation of the sulfinic group of both Hypotaurine and cysteine sulfinic acid with production of the respective sulfonate, taurine and cysteic acid is a crucial point for the generation of taurine in mammalian tissues (Wright et al., 1986; Huxtable, 1992). It has been proposed that the high levels of taurine found in tissues or cells such as sperm, neutrophils and retinal tissue (Pasantes-Morales et al., 1972; Alvarez and Storey, 1983; Learn et al., 1990; Green et al., 1991; Holmes et al., 1992) would reflect the turnover of Hypotaurine via oxidative reactions and might be viewed as an indirect measure of the oxidative stress associated with such tissues. However, the mechanism of the oxidative reaction of the sulfinic group is not yet clearly defined. Recently, it has been shown that, besides nonspecific oxidants such as UV irradiation, hypochlorite, hydroxyl radical and photochemically generated singlet oxygen, also peroxynitrite mediates the oxidation of both Hypotaurine and cysteine sulfinic acid to taurine and cysteic acid, respectively (Ricci et al., 1978; Green et al., 1985; Fellman et al., 1987; Pecci et al., 1999; Fontana et al., 2005). These findings have been related to the proposed role of Hypotaurine as an antioxidant and free radical trapping agent in vivo (Aruoma et al., 1988; Tadolini et al., 1995). According to this, Hypotaurine and cysteine sulfinic acid are able to prevent peroxynitrite-mediated reactions such as tyrosine nitration, α1-antiproteinase inactivation and low-density lipoprotein oxidative modification (Fontana et al., 2004). Peroxynitrite is a strong oxidizing and nitrating agent, which can be produced by the reaction of nitric oxide with superoxide anion (Koppenol et al., 1992; Huie and Padmaja, 1993; Pryor and Squadrito, 1995) and represents a reactive toxic species that can mediate cellular and tissue damage in various human diseases, including neurodegenerative disorders, inflammatory and autoimmune diseases (Eiserich et al., 1998; Stewart and Heales, 2003). At physiological pH both peroxynitrite anion (ONOO) and its conjugate
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antioxidant properties of sulfinates protective effect of Hypotaurine on peroxynitrite dependent damage
Neurochemical Research, 2004Co-Authors: Mario Fontana, Silvestro Dupre, Laura Pecci, D CavalliniAbstract:It has been proposed that Hypotaurine may function as an antioxidant in vivo. We investigated whether this compound can act as protective agent able to prevent damage from peroxynitrite, a strong oxidizing and nitrating agent that reacts with several biomolecules. The results showed that the compound efficiently protects tyrosine against nitration, α1-antiproteinase against inactivation, and human low-density lipoprotein against modification by peroxynitrite. Hypotaurine is also highly effective in inhibiting peroxynitrite-mediated nitration of tyrosine in the presence of added bicarbonate. This result suggests that Hypotaurine could play an important role as protective agent under physiological conditions. Moreover, it was found that cysteine sulfinic acid, but not taurine, possesses protective properties against peroxynitrite-dependent damage similar to Hypotaurine. These findings indicate that the protective effects exerted by these compounds may be attributable to the presence of the sulfinic group oxidizable into sulfonate by scavenging peroxynitrite and/or its derived species.
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Hypotaurine and superoxide dismutase
Advances in Experimental Medicine and Biology, 2002Co-Authors: Laura Pecci, Silvestro Dupre, Mara Costa, Gabriella Montefoschi, Mario Fontana, D CavalliniAbstract:Hypotaurine is able to prevent the inactivation of SOD by H2O2. The protectionis concentration-dependent: at 20 mM Hypotaurine the inactivation of SOD is completely prevented. It is likely that Hypotaurine exerts this effect by reacting with hydroxyl radicals, generated during the inactivation process, in competition with the sensitive group on the active site of the enzyme. According to this, spectral studies indicate that in presence of Hypotaurine the integrity of the active site of SOD is preserved by the disruptive action of H2O2 An interesting outcome of the SOD/H2O2/Hypotaurine interaction is that SOD catalyzes the peroxidation of Hypotaurine to taurine. Indeed, the formation of taurine increases with the reaction time and with the enzyme concentration. Although the peroxidase activity of SOD is not specific and relatively slow compared to the dismutation of superoxide, it might represent another valuable mechanism of production of taurine.
Silvestro Dupre - One of the best experts on this subject based on the ideXlab platform.
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the reactivity of Hypotaurine and cysteine sulfinic acid with peroxynitrite
Advances in Experimental Medicine and Biology, 2006Co-Authors: Mario Fontana, Silvestro Dupre, Laura PecciAbstract:The oxidation of the sulfinic group of both Hypotaurine and cysteine sulfinic acid with production of the respective sulfonate, taurine and cysteic acid is a crucial point for the generation of taurine in mammalian tissues (Wright et al., 1986; Huxtable, 1992). It has been proposed that the high levels of taurine found in tissues or cells such as sperm, neutrophils and retinal tissue (Pasantes-Morales et al., 1972; Alvarez and Storey, 1983; Learn et al., 1990; Green et al., 1991; Holmes et al., 1992) would reflect the turnover of Hypotaurine via oxidative reactions and might be viewed as an indirect measure of the oxidative stress associated with such tissues. However, the mechanism of the oxidative reaction of the sulfinic group is not yet clearly defined. Recently, it has been shown that, besides nonspecific oxidants such as UV irradiation, hypochlorite, hydroxyl radical and photochemically generated singlet oxygen, also peroxynitrite mediates the oxidation of both Hypotaurine and cysteine sulfinic acid to taurine and cysteic acid, respectively (Ricci et al., 1978; Green et al., 1985; Fellman et al., 1987; Pecci et al., 1999; Fontana et al., 2005). These findings have been related to the proposed role of Hypotaurine as an antioxidant and free radical trapping agent in vivo (Aruoma et al., 1988; Tadolini et al., 1995). According to this, Hypotaurine and cysteine sulfinic acid are able to prevent peroxynitrite-mediated reactions such as tyrosine nitration, α1-antiproteinase inactivation and low-density lipoprotein oxidative modification (Fontana et al., 2004). Peroxynitrite is a strong oxidizing and nitrating agent, which can be produced by the reaction of nitric oxide with superoxide anion (Koppenol et al., 1992; Huie and Padmaja, 1993; Pryor and Squadrito, 1995) and represents a reactive toxic species that can mediate cellular and tissue damage in various human diseases, including neurodegenerative disorders, inflammatory and autoimmune diseases (Eiserich et al., 1998; Stewart and Heales, 2003). At physiological pH both peroxynitrite anion (ONOO) and its conjugate
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antioxidant properties of sulfinates protective effect of Hypotaurine on peroxynitrite dependent damage
Neurochemical Research, 2004Co-Authors: Mario Fontana, Silvestro Dupre, Laura Pecci, D CavalliniAbstract:It has been proposed that Hypotaurine may function as an antioxidant in vivo. We investigated whether this compound can act as protective agent able to prevent damage from peroxynitrite, a strong oxidizing and nitrating agent that reacts with several biomolecules. The results showed that the compound efficiently protects tyrosine against nitration, α1-antiproteinase against inactivation, and human low-density lipoprotein against modification by peroxynitrite. Hypotaurine is also highly effective in inhibiting peroxynitrite-mediated nitration of tyrosine in the presence of added bicarbonate. This result suggests that Hypotaurine could play an important role as protective agent under physiological conditions. Moreover, it was found that cysteine sulfinic acid, but not taurine, possesses protective properties against peroxynitrite-dependent damage similar to Hypotaurine. These findings indicate that the protective effects exerted by these compounds may be attributable to the presence of the sulfinic group oxidizable into sulfonate by scavenging peroxynitrite and/or its derived species.
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Hypotaurine and superoxide dismutase
Advances in Experimental Medicine and Biology, 2002Co-Authors: Laura Pecci, Silvestro Dupre, Mara Costa, Gabriella Montefoschi, Mario Fontana, D CavalliniAbstract:Hypotaurine is able to prevent the inactivation of SOD by H2O2. The protectionis concentration-dependent: at 20 mM Hypotaurine the inactivation of SOD is completely prevented. It is likely that Hypotaurine exerts this effect by reacting with hydroxyl radicals, generated during the inactivation process, in competition with the sensitive group on the active site of the enzyme. According to this, spectral studies indicate that in presence of Hypotaurine the integrity of the active site of SOD is preserved by the disruptive action of H2O2 An interesting outcome of the SOD/H2O2/Hypotaurine interaction is that SOD catalyzes the peroxidation of Hypotaurine to taurine. Indeed, the formation of taurine increases with the reaction time and with the enzyme concentration. Although the peroxidase activity of SOD is not specific and relatively slow compared to the dismutation of superoxide, it might represent another valuable mechanism of production of taurine.
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Hypotaurine protection on cell damage by singlet oxygen
Advances in Experimental Medicine and Biology, 2002Co-Authors: Giuseppina Pitari, Silvestro Dupre, Alessandra Spirito, Giovanni Antonini, Fernanda AmicarelliAbstract:Singlet oxygen (1O2), generated byirradiating methylene blue, is toxic to melanoma cell cultures. Hypotaurine is known to scavenge efficiently singlet oxygen; the addition of Hypotaurine (800 μM) to the medium during irradiation of the dye produces a greater protective effect on cells than taurine added at the same concentration. The assay of some detoxifying enzymatic activities indicate a different mechanism of protection of the two molecules: taurine induces anefficient detoxifying enzymatic action with respect to the control; Hypotaurine exerts its effect greatly by specifically scavenging singlet oxygen.
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biochemical and ultrastructural alaterations is rat after hyperoxic treatment effect of taurine and Hypotaurine
Advances in Experimental Medicine and Biology, 2002Co-Authors: Giuseppina Pitari, Silvestro Dupre, Anna Maria Ragnelli, Pierpaolo Aimola, Camillo Di Giulio, Fernanda AmicarelliAbstract:The cell ultrastructure and some detoxifying enzyme activities were studied in skeletal muscles of young rats kept for 84 h under normobaric hyperoxia (95% O2) or normoxia as control. Rat were injected ip. Every 12 h either with lml saline, 1 ml saline +30 mg Hypotaurine or 1 ml saline +30 mg taurine. Ultrastructural observation revealed an highly protective effect on tissue damages due to hyperoxia in taurinetreated rats and, at less extent, in Hypotaurine-treated ones. Enzymatic assays suggest a different mechanism of the two molecules in their protective action.
Laura Pecci - One of the best experts on this subject based on the ideXlab platform.
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reactivity of Hypotaurine and cysteine sulfinic acid toward carbonate radical anion and nitrogen dioxide as explored by the peroxidase activity of cu zn superoxide dismutase and by pulse radiolysis
Free Radical Research, 2014Co-Authors: Baseggio A Conrado, Laura Pecci, M Dangelantonio, A Torreggiani, Mario FontanaAbstract:AbstractHypotaurine and cysteine sulfinic acid are known to be readily oxidized to the respective sulfonates, taurine and cysteic acid, by several oxidative agents that may be present in biological systems. In this work, the relevance of both the carbonate anion and nitrogen dioxide radicals in the oxidation of Hypotaurine and cysteine sulfinic acid has been explored by the peroxidase activity of Cu,Zn superoxide dismutase (SOD) and by pulse radiolysis. The extent of sulfinate oxidation induced by the system SOD/H2O2 in the presence of bicarbonate (CO3•– generation), or nitrite (•NO2 generation) has been evaluated. Hypotaurine is efficiently oxidized by the carbonate radical anion generated by the peroxidase activity of Cu,Zn SOD. Pulse radiolysis studies have shown that the carbonate radical anion reacts with Hypotaurine more rapidly (k = 1.1 × 109 M−1s−1) than nitrogen dioxide (k = 1.6 × 107 M−1s−1). Regarding cysteine sulfinic acid, it is less reactive with the carbonate radical anion (k = 5.5 × 107 M−...
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the reactivity of Hypotaurine and cysteine sulfinic acid with peroxynitrite
Advances in Experimental Medicine and Biology, 2006Co-Authors: Mario Fontana, Silvestro Dupre, Laura PecciAbstract:The oxidation of the sulfinic group of both Hypotaurine and cysteine sulfinic acid with production of the respective sulfonate, taurine and cysteic acid is a crucial point for the generation of taurine in mammalian tissues (Wright et al., 1986; Huxtable, 1992). It has been proposed that the high levels of taurine found in tissues or cells such as sperm, neutrophils and retinal tissue (Pasantes-Morales et al., 1972; Alvarez and Storey, 1983; Learn et al., 1990; Green et al., 1991; Holmes et al., 1992) would reflect the turnover of Hypotaurine via oxidative reactions and might be viewed as an indirect measure of the oxidative stress associated with such tissues. However, the mechanism of the oxidative reaction of the sulfinic group is not yet clearly defined. Recently, it has been shown that, besides nonspecific oxidants such as UV irradiation, hypochlorite, hydroxyl radical and photochemically generated singlet oxygen, also peroxynitrite mediates the oxidation of both Hypotaurine and cysteine sulfinic acid to taurine and cysteic acid, respectively (Ricci et al., 1978; Green et al., 1985; Fellman et al., 1987; Pecci et al., 1999; Fontana et al., 2005). These findings have been related to the proposed role of Hypotaurine as an antioxidant and free radical trapping agent in vivo (Aruoma et al., 1988; Tadolini et al., 1995). According to this, Hypotaurine and cysteine sulfinic acid are able to prevent peroxynitrite-mediated reactions such as tyrosine nitration, α1-antiproteinase inactivation and low-density lipoprotein oxidative modification (Fontana et al., 2004). Peroxynitrite is a strong oxidizing and nitrating agent, which can be produced by the reaction of nitric oxide with superoxide anion (Koppenol et al., 1992; Huie and Padmaja, 1993; Pryor and Squadrito, 1995) and represents a reactive toxic species that can mediate cellular and tissue damage in various human diseases, including neurodegenerative disorders, inflammatory and autoimmune diseases (Eiserich et al., 1998; Stewart and Heales, 2003). At physiological pH both peroxynitrite anion (ONOO) and its conjugate
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antioxidant properties of sulfinates protective effect of Hypotaurine on peroxynitrite dependent damage
Neurochemical Research, 2004Co-Authors: Mario Fontana, Silvestro Dupre, Laura Pecci, D CavalliniAbstract:It has been proposed that Hypotaurine may function as an antioxidant in vivo. We investigated whether this compound can act as protective agent able to prevent damage from peroxynitrite, a strong oxidizing and nitrating agent that reacts with several biomolecules. The results showed that the compound efficiently protects tyrosine against nitration, α1-antiproteinase against inactivation, and human low-density lipoprotein against modification by peroxynitrite. Hypotaurine is also highly effective in inhibiting peroxynitrite-mediated nitration of tyrosine in the presence of added bicarbonate. This result suggests that Hypotaurine could play an important role as protective agent under physiological conditions. Moreover, it was found that cysteine sulfinic acid, but not taurine, possesses protective properties against peroxynitrite-dependent damage similar to Hypotaurine. These findings indicate that the protective effects exerted by these compounds may be attributable to the presence of the sulfinic group oxidizable into sulfonate by scavenging peroxynitrite and/or its derived species.
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Hypotaurine and superoxide dismutase
Advances in Experimental Medicine and Biology, 2002Co-Authors: Laura Pecci, Silvestro Dupre, Mara Costa, Gabriella Montefoschi, Mario Fontana, D CavalliniAbstract:Hypotaurine is able to prevent the inactivation of SOD by H2O2. The protectionis concentration-dependent: at 20 mM Hypotaurine the inactivation of SOD is completely prevented. It is likely that Hypotaurine exerts this effect by reacting with hydroxyl radicals, generated during the inactivation process, in competition with the sensitive group on the active site of the enzyme. According to this, spectral studies indicate that in presence of Hypotaurine the integrity of the active site of SOD is preserved by the disruptive action of H2O2 An interesting outcome of the SOD/H2O2/Hypotaurine interaction is that SOD catalyzes the peroxidation of Hypotaurine to taurine. Indeed, the formation of taurine increases with the reaction time and with the enzyme concentration. Although the peroxidase activity of SOD is not specific and relatively slow compared to the dismutation of superoxide, it might represent another valuable mechanism of production of taurine.
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oxidation of Hypotaurine to taurine with photochemically generated singlet oxygen the effect of azide
Biochemical and Biophysical Research Communications, 1999Co-Authors: Laura Pecci, Mara Costa, Gabriella Montefoschi, A Antonucci, D CavalliniAbstract:Hypotaurine is oxidized to taurine by singlet oxygen (1O2) generated with methylene blue used as a photosensitizer. The oxidation rate increases in the presence of deuterium oxide as expected for the involvement of1O2. Addition of the1O2quencher azide also produced an activating effect in contrast with the expected inhibition. Azidyl radicals produced by the oxidation of azide by the horseradish peroxidase/hydrogen peroxide system stimulate the oxidation of the added Hypotaurine. It is concluded that azide competes with Hypotaurine for1O2generating the azidyl radical which is a strong one-electron oxidant transfer of the radical to Hypotaurine. The Hypotaurine radical is then converted into taurine, possibly through the disulfone intermediate. Formation of the sulfonic hydroperoxide is the possible intermediate in the absence of azide. The finding that the azidyl radical efficiently oxidizes Hypotaurine to its metabolic product taurine raises the expectation of Hypotaurine being a valuable scavenger of endogenous and exogenous radicals.
D Cavallini - One of the best experts on this subject based on the ideXlab platform.
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antioxidant properties of sulfinates protective effect of Hypotaurine on peroxynitrite dependent damage
Neurochemical Research, 2004Co-Authors: Mario Fontana, Silvestro Dupre, Laura Pecci, D CavalliniAbstract:It has been proposed that Hypotaurine may function as an antioxidant in vivo. We investigated whether this compound can act as protective agent able to prevent damage from peroxynitrite, a strong oxidizing and nitrating agent that reacts with several biomolecules. The results showed that the compound efficiently protects tyrosine against nitration, α1-antiproteinase against inactivation, and human low-density lipoprotein against modification by peroxynitrite. Hypotaurine is also highly effective in inhibiting peroxynitrite-mediated nitration of tyrosine in the presence of added bicarbonate. This result suggests that Hypotaurine could play an important role as protective agent under physiological conditions. Moreover, it was found that cysteine sulfinic acid, but not taurine, possesses protective properties against peroxynitrite-dependent damage similar to Hypotaurine. These findings indicate that the protective effects exerted by these compounds may be attributable to the presence of the sulfinic group oxidizable into sulfonate by scavenging peroxynitrite and/or its derived species.
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Hypotaurine and superoxide dismutase
Advances in Experimental Medicine and Biology, 2002Co-Authors: Laura Pecci, Silvestro Dupre, Mara Costa, Gabriella Montefoschi, Mario Fontana, D CavalliniAbstract:Hypotaurine is able to prevent the inactivation of SOD by H2O2. The protectionis concentration-dependent: at 20 mM Hypotaurine the inactivation of SOD is completely prevented. It is likely that Hypotaurine exerts this effect by reacting with hydroxyl radicals, generated during the inactivation process, in competition with the sensitive group on the active site of the enzyme. According to this, spectral studies indicate that in presence of Hypotaurine the integrity of the active site of SOD is preserved by the disruptive action of H2O2 An interesting outcome of the SOD/H2O2/Hypotaurine interaction is that SOD catalyzes the peroxidation of Hypotaurine to taurine. Indeed, the formation of taurine increases with the reaction time and with the enzyme concentration. Although the peroxidase activity of SOD is not specific and relatively slow compared to the dismutation of superoxide, it might represent another valuable mechanism of production of taurine.
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oxidation of Hypotaurine to taurine with photochemically generated singlet oxygen the effect of azide
Biochemical and Biophysical Research Communications, 1999Co-Authors: Laura Pecci, Mara Costa, Gabriella Montefoschi, A Antonucci, D CavalliniAbstract:Hypotaurine is oxidized to taurine by singlet oxygen (1O2) generated with methylene blue used as a photosensitizer. The oxidation rate increases in the presence of deuterium oxide as expected for the involvement of1O2. Addition of the1O2quencher azide also produced an activating effect in contrast with the expected inhibition. Azidyl radicals produced by the oxidation of azide by the horseradish peroxidase/hydrogen peroxide system stimulate the oxidation of the added Hypotaurine. It is concluded that azide competes with Hypotaurine for1O2generating the azidyl radical which is a strong one-electron oxidant transfer of the radical to Hypotaurine. The Hypotaurine radical is then converted into taurine, possibly through the disulfone intermediate. Formation of the sulfonic hydroperoxide is the possible intermediate in the absence of azide. The finding that the azidyl radical efficiently oxidizes Hypotaurine to its metabolic product taurine raises the expectation of Hypotaurine being a valuable scavenger of endogenous and exogenous radicals.
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in vitro reactions of Hypotaurine
Advances in Experimental Medicine and Biology, 1996Co-Authors: Silvestro Dupre, Mario Fontana, Giuseppina Pitari, D CavalliniAbstract:Hypotaurine and cysteine sulfinic acid are natural sulfinates found in relatively low amounts in some mammalian tissues5. They are metabolic intermediates in the biosynthetic pathways leading to the corresponding sulfonates. The function of Hypotaurine as a biological antioxidant in protecting some cells from oxidative damage, by scavenging free radical forms of oxygen, has been proposed in the past3, 9 and recently demonstrated in vitro.1, 4 Chemically, sulfinates are not very stable compounds; oxidation is the most important but not the only reaction they are involved in. The low content of natural sulfinates in physiological tissues or fluids makes it often necessary, to perform quantitative determinations, to submit the biological samples to enrichment procedures which could give rise to artefactual results. The presence of an acidic milieu was supposed to slow down the oxidation of Hypotaurine to taurine, which is enhanced at alkaline pH. However, it seems that oxidation is also facilitated in the presence of deproteinizing acids such as sulfosalycilic acid3 or trichloroacetic acid.
Matan Hofree - One of the best experts on this subject based on the ideXlab platform.
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association of methylation of genes in the taurine Hypotaurine pathway with worse prognosis in renal cell carcinoma
Journal of Clinical Oncology, 2013Co-Authors: Andrew M Gross, Michel Choueiri, John Paul Shen, James Michael Randall, Trey Ideker, Matan HofreeAbstract:e15562 Background: Epigenetic silencing of genes associated with the taurine/Hypotaurine pathway has been associated with worse outcome in several tumors such as CDO1 in breast cancer, and GAD1 in prostate cancer. Our objective was to assess the prognostic value of methylation status of genes in the taurine/Hypotaurine pathway in patients with renal cell carcinoma (RCC). Methods: We performed an analysis of 283 RCC samples using data from The Cancer Genome Atlas (TCGA). Ten genes belonging to the taurine/Hypotaurine metabolic were analyzed using principal component analysis to determine a composite methylation profile of the pathway. A Cox proportional-hazards regression model was then used to determine the association of the composite methylation profile with patient survival. Results: CDO1, GAD2, and GAD1 influenced the outcome of the composite gene the most. Increasing degree of methylation correlated with more advanced tumor stage, and was an independent predictor of overall patient survival. Among pa...
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Association of methylation of genes in the taurine/Hypotaurine pathway with worse prognosis in renal cell carcinoma.
Journal of Clinical Oncology, 2013Co-Authors: Andrew M Gross, Michel Choueiri, John Paul Shen, James Michael Randall, Trey Ideker, Matan HofreeAbstract:e15562 Background: Epigenetic silencing of genes associated with the taurine/Hypotaurine pathway has been associated with worse outcome in several tumors such as CDO1 in breast cancer, and GAD1 in prostate cancer. Our objective was to assess the prognostic value of methylation status of genes in the taurine/Hypotaurine pathway in patients with renal cell carcinoma (RCC). Methods: We performed an analysis of 283 RCC samples using data from The Cancer Genome Atlas (TCGA). Ten genes belonging to the taurine/Hypotaurine metabolic were analyzed using principal component analysis to determine a composite methylation profile of the pathway. A Cox proportional-hazards regression model was then used to determine the association of the composite methylation profile with patient survival. Results: CDO1, GAD2, and GAD1 influenced the outcome of the composite gene the most. Increasing degree of methylation correlated with more advanced tumor stage, and was an independent predictor of overall patient survival. Among pa...