Endogenous Metabolite

Endogenous metabolites are those that the Kyoto Encyclopedia of Genes and Genomes has identified as products or substrates of the approximately 1900 metabolic enzymes that are encoded in human genome. Numerous of these metabolites have been shown to have harmful effects, as evidenced by the body of literature [1].

[1]. Endogenous toxic metabolites and implications in cancer therapy. Oncogene. 2020 Aug;39(35):5709-5720.
[2]. Capillary electrophoresis-mass spectrometry-based metabolome analysis of serum and saliva from neurodegenerative dementia patients. Electrophoresis. 2013 Oct;34(19):2865-72.
[3]. Intracellular flux analysis applied to the effect of dissolved oxygen on hybridomas. Appl Microbiol Biotechnol. 1995 Dec;44(1-2):27-36.

Isocitric is a tricarboxylic acid, specifically propan-1-ol, in which the hydrogen atoms on all three carbon atoms are replaced by carboxyl groups. It is an important metabolite. It is both a tricarboxylic acid and a secondary alcohol. It is the conjugate acid of Isocitric (1-). Isocitric is a metabolite found or produced in Escherichia coli (strains K12 and MG1655). It has also been reported to be present in Aspen, Blueberry, and other organisms with relevant data. Isocitric is a metabolite found or produced in Saccharomyces cerevisiae. It is well known that many metabolic enzymes play crucial roles in cancer cells, responsible for synthesizing building blocks such as nucleotides, which cancer cells require large amounts of formic acid proliferation. However, the importance of enzymes in preventing the accumulation of their substrates is less well understood. This article outlines the evidence and potential mechanisms by which many normally produced metabolites in cells are highly toxic, such as metabolites containing active groups (e.g., methylglyoxal, 4-hydroxynonenal, and gamma-glutamyl-CoA) or metabolites that are competitive analogs of other metabolites (e.g., deoxyuridine triphosphate and L-2-hydroxyglutarate). Thus, if a metabolic pathway involves a toxic intermediate, we can induce its accumulation and poison cancer cells by targeting downstream enzymes. Furthermore, if the pathway is overactive in cancer cells relative to non-transformed cells, this toxicity may be cancer cell selective. We illustrate this concept with selenocysteine metabolism and other pathways as examples and discuss future directions for using toxic metabolites to kill cancer cells. [1] Despite the rising global prevalence of neurodegenerative dementia, its exact pathogenesis and objective diagnostic terminology remain controversial, and a comprehensive understanding of the disease is still lacking. This study performed metabolomics analysis on serum and saliva samples from 10 patients with neurodegenerative dementia (including Alzheimer's disease, frontotemporal dementia, and Lewy body dementia) and 9 age-matched healthy controls. Using capillary electrophoresis-time-of-flight mass spectrometry (CE-TOF-MS), we found significant differences in the levels of six metabolites (β-alanine, creatinine, hydroxyproline, glutamine, Isocitric, and cytidine) in the serum of dementia patients and healthy controls, and two metabolites (arginine and tyrosine) in their saliva. Multivariate analysis confirmed that serum is a more effective diagnostic biological fluid than saliva; furthermore, 45 metabolites were identified as candidate biomarkers capable of distinguishing at least one pair of diagnosed groups from healthy controls. These metabolites hold promise for providing an objective diagnostic method for multi-stage screening of dementia types. In addition, diagnostic type-dependent differences were observed among several tricarboxylic acid cycle compounds detected in serum, suggesting that glucose metabolism pathways may be altered in dementia patients. This preliminary study reveals new changes in metabolomics characteristics among different neurodegenerative dementias, which will contribute to etiological research. [2]

---

The effects of dissolved oxygen (DO) concentration on batch-cultured CRL 1606 hybridoma cells were assessed using quantitative estimation of intracellular flux and measurements of intracellular concentration. The estimation of intracellular flux was generated by combining material balance with measurements of the rate of change of extracellular metabolites. Experiments were conducted at DO levels of 60% and 1% air saturation and under oxygen restriction conditions. Cell extracts were analyzed to assess the effects of DO on intracellular concentrations of glutamate dehydrogenase reactants and the redox state of pyridine nucleotides in the cytosol and mitochondria. The relationship between cell density and pyridine nucleotide redox state was also investigated. Dissolved oxygen concentration had a significant effect on nitrogen metabolism, and the flux of glutamate dehydrogenase was reversed under low dissolved oxygen conditions, which favored glutamate production. Under low dissolved oxygen conditions, the reduced state of NAD+ in the cytosol and mitochondria was enhanced, while the oxidized state of NAD+ in the cytosol was enhanced. The higher the cell density, the stronger the cytoplasmic NAD+ reduced state, while the redox states of cytoplasmic NADP+ and mitochondrial NAD+ did not change significantly with cell density. These results indicate that intracellular redox status plays a crucial role in cell physiology and suggest that physiological processes can be controlled by regulating dissolved oxygen levels or redox potential in the culture. [3]

C6H8O7

192.12

192.027

320-77-4

DL-Isocitric acid trisodium salt;1637-73-6

1198

Typically exists as White to off-white solid at room temperature

1.751g/cm3

329.6ºC at 760 mmHg

162 - 165 °C

167.4ºC

1.569

-1.8

4

7

5

13

233

0

OC(CC(C(C(=O)O)O)C(=O)O)=O

ODBLHEXUDAPZAU-UHFFFAOYSA-N

InChI=1S/C6H8O7/c7-3(8)1-2(5(10)11)4(9)6(12)13/h2,4,9H,1H2,(H,7,8)(H,10,11)(H,12,13)

1-hydroxypropane-1,2,3-tricarboxylic acid

isocitric acid; 320-77-4; isocitrate; 1-Hydroxypropane-1,2,3-tricarboxylic acid; 3-Carboxy-2,3-dideoxy-1-hydroxypropan-1,2,3-tricarboxylic acid; DL-Isocitric acid; 3-carboxy-2,3-dideoxypentaric acid; 1-Hydroxytricarballylic 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)

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.

---

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).

View More

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)

---

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).

View More

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

---

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.

---

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