IC50: L-aspartate-β-semialdehyde dehydrogenase (ASADH)[1]
L-Aspartate-β-semialdehyde dehydrogenase (ASADH). D-Cystine functions as an inhibitor of L-aspartate-β-semialdehyde dehydrogenase (ASADH) from Escherichia coli. ASADH is an enzyme involved in the biosynthesis of amino acids. The compound is also used to study stereospecific enzyme activity, chiral recognition, and oxidative folding mechanisms. D-Cysteine, derived from D-cystine, is a key substrate in a novel pathway for the production of the gasotransmitter hydrogen sulfide (H₂S).

D-Cystine inhibits L-aspartate-β-semialdehyde dehydrogenase (ASADH) from Escherichia coli. D-Cysteine, derived from D-cystine, is a key substrate in a novel pathway for the production of the gasotransmitter hydrogen sulfide (H₂S). The compound is used to study stereospecific enzyme activity, chiral recognition, and oxidative folding mechanisms. It serves as a building block in the preparation of peptidomimetics, synthetic scaffolds, and drug delivery systems requiring disulfide-linked release mechanisms.

In vivo studies of D-cystine are limited. As the D-enantiomer of cystine, it is used to study the role of D-amino acids in biological systems. D-Cysteine, derived from D-cystine, is a key substrate in a novel pathway for the production of H₂S. The compound’s role in oxidative folding and disulfide bond formation makes it relevant for studying protein structure and function. Further in vivo studies are needed to characterize its pharmacokinetic and pharmacodynamic properties.

Non-cell-based assays for D-cystine include ASADH enzyme inhibition assays using purified enzyme. The enzyme is incubated with substrate (L-aspartate-β-semialdehyde) and NADPH in the presence of various concentrations of D-cystine, and enzyme activity is measured by monitoring NADPH consumption spectrophotometrically. Standard analytical methods including HPLC, NMR, and mass spectrometry are used for compound characterization and purity assessment.

Cell-based assays for D-cystine use bacterial cultures (E. coli) to assess ASADH inhibition. Bacterial cells are treated with the compound, and growth inhibition or changes in amino acid biosynthesis are measured. For studies of H₂S production, mammalian cell lines or tissues are used to assess the conversion of D-cysteine to H₂S. Cytotoxicity is assessed using standard cell viability assays.

In vivo studies of D-cystine are limited. Potential animal models include: models for studying H₂S production and its physiological effects; models for studying amino acid metabolism; and models for evaluating the therapeutic potential of D-amino acids. Standard protocols for these models involve administration of the compound followed by measurement of relevant endpoints.

D-Cystine has a molecular formula of C₆H₁₂N₂O₄S₂ and a molecular weight of 240.30 g/mol. Purity is ≥98%. It is the D-enantiomer of L-cystine and the oxidized dimeric form of D-cysteine. The compound should be stored under recommended conditions. It is intended for research use only.

Specific toxicity data for D-cystine are limited. As a naturally occurring amino acid derivative, it is generally considered to have low toxicity. Standard laboratory safety practices should be followed when handling this compound.

[1]. Emilio Alvarez, et al. L-cystine inhibits aspartate-beta-semialdehyde dehydrogenase by covalently binding to the essential 135Cys of the enzyme. Biochim Biophys Acta. 2004 Jan 14;1696(1):23-9.

D-Cysteine is the D-enantiomer of cystine. It is an EC 1.2.1.11 (aspartate semialdehyde dehydrogenase) inhibitor. It is the enantiomer of L-cystine and also the zwitterion tautomer of D-cystine. Cystine is a covalently linked dimer, non-essential amino acid formed by the oxidation of cysteine. Two cysteine molecules are linked by a disulfide bond to form cystine. D-Cysteine has been reported to be found in soybean (Glycine max), morel (Morchella esculenta), and several other organisms with relevant data. Cystine is not one of the 20 essential amino acids. Cystine is a sulfur-containing derivative formed by the oxidation of the thiol side chain of cysteine amino acids. It has antioxidant properties, protecting tissues from radiation and pollution damage and slowing down the aging process. It also contributes to protein synthesis. Cystine is abundant in many proteins in bone tissue and skin, and is also found in insulin and digestive enzymes such as chromaffin protrypsin A, papain, and trypsinogen. (NCI04)
Cysteine is a covalently linked dimer, non-essential amino acid formed by the oxidation of cysteine. Two cysteine molecules are linked by a disulfide bond to form cysteine.

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Drug Indications
L-cysteine is claimed to have anti-inflammatory properties, can combat a variety of toxins, and may help treat osteoarthritis and rheumatoid arthritis. Further research is needed before L-cysteine can be used to treat any of these diseases. Research to date has primarily focused on animal models.

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Mechanism of Action
In certain situations, such as acetaminophen overdose, glutathione in the liver is depleted, causing oxidative stress in tissues and leading to loss of cellular integrity. L-cysteine is a major precursor in the synthesis of glutathione.

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D-Cystine is the D-enantiomer of L-cystine, the oxidized dimeric form of D-cysteine. It functions as an inhibitor of L-aspartate-β-semialdehyde dehydrogenase (ASADH) from Escherichia coli. D-Cysteine, derived from D-cystine, is a key substrate in a novel pathway for the production of the gasotransmitter hydrogen sulfide (H₂S). The compound is used to study stereospecific enzyme activity, chiral recognition, and oxidative folding mechanisms. It serves as a building block for peptidomimetics and drug delivery systems and is for research use only.

C6H12N2O4S2

240.30

240.023

349-46-2

6857538

White to yellow solid powder

1.6±0.1 g/cm3

468.2±45.0 °C at 760 mmHg

260ºC

237.0±28.7 °C

0.0±2.5 mmHg at 25°C

1.653

1.23

4

8

7

14

192

2

C([C@H](C(=O)O)N)SSC[C@H](C(=O)O)N

LEVWYRKDKASIDU-QWWZWVQMSA-N

InChI=1S/C6H12N2O4S2/c7-3(5(9)10)1-13-14-2-4(8)6(11)12/h3-4H,1-2,7-8H2,(H,9,10)(H,11,12)/t3-,4-/m1/s1

(2S)-2-amino-3-[[(2S)-2-amino-2-carboxyethyl]disulfanyl]propanoic acid

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)

DMSO: < 1 mg/mL

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.)