Metabolic product of cystine

Thiotaurine, a metabolic product of cystine, contains a sulfane sulfur atom that can be released as H(2)S, a gaseous molecule with a regulatory activity on inflammatory responses. The influence of thiotaurine on human leukocyte spontaneous apoptosis has been evaluated by measuring caspase-3 activity in human neutrophils. Addition of 100 μM thiotaurine induced a 55% inhibition of caspase-3 activity similar to that exerted by 100 μM H(2)S. Interestingly, in the presence of 1 mM GSH, an increase of the inhibition of apoptosis by thiotaurine has been observed. These results indicate that the bioactivity of thiotaurine can be modulated by GSH, which promotes the reductive breakdown of the thiosulfonate generating H(2)S and hypotaurine. As thiotaurine is able to incorporate reversibly reduced sulfur, it is suggested that the biosynthesis of this thiosulfonate could be a means to transport and store H(2)S [1].

Thiotaurine is an effective antioxidant agent as demonstrated by its ability to counteract the damage caused by pro-oxidants in the rat [2].

Thiotaurine is a thiosulfonate compound bearing a sulfane sulfur atom metabolically generated in body fluids and tissues. Thiotaurine constitutes an interconnection molecule between aerobic and anaerobic pathways of cysteine metabolism. Thiotaurine formed as a result of the reaction between hypotaurine and sulfide may be converted back to H2S and hypotaurine. Thus, thiotaurine may be considered as a safe, non-toxic storage form of H2S and an important key intermediate in the biochemical routes of transport, storage and release of sulfide. Sulfane sulfur-containing compounds efficiently regulate the activity of enzymes and exhibit antioxidative properties. Interestingly, thiotaurine influences inflammatory processes modulating functional responses of human neutrophils and exhibits a protective effect against oxidative damage [2].

Influence of Thiotaurine on Human Neutrophil Spontaneous Apoptosis[1]
Spontaneous apoptosis was evaluated by measuring caspase-3 activity in lysates of neutrophils (5  ×  106 cells/mL) that were preincubated at 37°C for 3.5 h. When the preincubation step was performed in the presence of thiotaurine (TTAU), a concentration-dependent decrease of caspase-3 activity was observed (Fig. 19.1). As thiotaurine contains a sulfane sulfur atom that can be released as H2S, the influence of NaHS on caspase-3 activity has been also evaluated. With 100 μM thiotaurine the reduction of caspase-3 activity was 55  ±  3%, similar to that exhibited by 100 μM NaHS (57  ±  3%). Control experiments (not shown) indicated that neither TTAU, nor NaHS, at concentrations ranging from 0.01 to 0.2 mM, affected the activity of recombinant caspase-3.

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Effect of Glutathione on Thiotaurine-Induced Inhibition of Caspase-3 Activity[1]
It is reported that glutathione (GSH) regulates neutrophil apoptosis by affecting caspase-3 activity (O’Neill et al. 2000). This effect has been attributed to its antioxidant activity (Wedi et al. 1999). To gain insights into the mechanism of inhibition by TTAU, the inhibitory effect of this thiosulfonate on caspase-3 activity has been compared with that of GSH (Fig. 19.2).

[1]. Adv Exp Med Biol. 2013:775:227-36. doi: 10.1007/978-1-4614-6130-2_19.
[2]. Adv Exp Med Biol. 2019:1155:755-771. doi: 10.1007/978-981-13-8023-5_66.

These results suggest that the thiosulfonate compound thiotaurine may affect the lifespan of human neutrophils by modulating the inflammatory response. Mature circulating neutrophils are inherently prone to apoptosis. During the inflammatory response, the survival time of neutrophils recruited to the inflammatory region is significantly prolonged. This prolonged survival time in inflamed tissue allows neutrophils to perform their effector functions more effectively. On the other hand, macrophage-mediated clearance of apoptotic neutrophils from inflammatory regions has been considered a key mechanism for promoting inflammatory resolution (Savill and Fadok, 2000; Simon, 2003). It has been recognized that reactive oxygen species (ROS) produced by activated cells accelerate apoptosis, and the release of superoxide dismutase (SOD) is essential for spontaneous apoptosis (Ottonello et al., 2002; Scheel-Toellner et al., 2004). Furthermore, antioxidants, such as glutathione (GSH), can inhibit both spontaneous and fatty acid synthase (FAS)-mediated apoptosis (Wedi et al., 1999). This effect is attributed to the ability of GSH to scavenge ROS (Watson et al., 1997). Studies have also shown that thiotaurine can effectively counteract the damaging effects of oxidants (Acharya and Lau-Cam, 2012). Therefore, the delay in spontaneous apoptosis of human neutrophils by thiotaurine may be related to its antioxidant activity. On the other hand, our results indicate that thiotaurine has a stronger inhibitory effect on caspase-3 activity than GSH. Furthermore, the effect of thiotaurine on neutrophil apoptosis is more significant in the presence of GSH. These findings suggest the possible existence of other or additional inhibitory mechanisms. It is well known that glutathione (GSH) catalyzes the reductive breakdown of thiotaurine to generate taurine and hydrogen sulfide (H₂S) (Chauncey and Westley, 1983). Therefore, we found that human neutrophils utilize thiotaurine to generate H₂S in the presence of GSH as a necessary reducing agent. Previous reports have indicated that H₂S can promote short-term neutrophil survival by inhibiting caspase-3 cleavage (Rinaldi et al., 2006). Our results confirm the role of H₂S in prolonging neutrophil survival. Therefore, the release of thioalkyl sulfur from thiotaurine as H₂S in the presence of GSH may contribute to the observed neutrophil survival effect. [1] The biological significance of thiotaurine in mammals remains a challenge for biochemical research. The biological functions of thiotaurine have been reported sporadically (Costa et al. 1990; Baskin et al. 2000). In contrast, thiotaurine plays a key role in sulfur transport in some marine organisms, which has been well demonstrated (Pruski et al. 2001; Pruski and Fiala-Médioni 2003). Furthermore, the metabolic sources and final metabolic pathways of thiotaurine in mammals remain controversial. One of the metabolic pathways of thiotaurine is through transsulfurization, in which taurine is the main intermediate (Cavallini et al. 1961; De Marco and Tentori 1961). These reactions can occur spontaneously or be catalyzed by thiotransferases (De Marco et al. 1961; Chauncey and Westley 1983). Our experiments showed that taurine is the major metabolite of thiotaurine, with a stoichiometric ratio of 1:1, suggesting that thiotaurine may act as a biochemical intermediate in the transport, storage, and release of sulfides in mammals. This hypothesis is also supported by the fact that taurine is present in millimolecular concentrations in leukocytes (Learn et al., 1990) and can rapidly bind to H₂S generated during inflammation to produce thiotaurine (De Marco and Tentori, 1961). [1] Since thiotaurine, taurine, taurine, and H₂S all regulate leukocyte functional responses, it is worthwhile to study the metabolic and functional interactions of these sulfur-containing compounds at sites of inflammation. [1]

141.21248

140.992

2937-54-4

31999-89-0 (mono-hydrochloride salt);2937-54-4 (Parent)

6858023

Solid

1.541g/cm3

324.6ºC at 760mmHg

150.1ºC

4.94E-05mmHg at 25°C

1.622

0.894

2

4

2

7

137

0

NCCS(=S)(O)=O

SHWIJIJNPFXOFS-UHFFFAOYSA-N

InChI=1S/C2H7NO2S2/c3-1-2-7(4,5)6/h1-3H2,(H,4,5,6)

2-hydroxysulfonothioylethanamine

Thiotaurine; 2-hydroxysulfonothioylethanamine; 2-Aminoethanethiosulfonic acid; NQZ2D7AO62; Thiotaurine; 2937-54-4; 2-hydroxysulfonothioylethanamine; 2-Aminoethanethiosulfonic acid; NQZ2D7AO62; Sodium 2-aminosulphonothioacetate; EINECS 250-888-0; 31999-89-0;

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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 (Please use freshly prepared in vivo formulations for optimal results.)