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Showing 141 - 160 of 78500 compounds

Compound ID

Compound

Pathways

PW_C000148

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Oxalacetic acid

Oxaloacetic acid, also known as oxosuccinic acid or oxalacetic acid, is a four-carbon dicarboxylic acid appearing as an intermediate of the citric acid cycle. In vivo, oxaloacetate (the ionized form of oxaloacetic acid) is formed by the oxidation of L-malate, catalyzed by malate dehydrogenase, and reacts with Acetyl-CoA to form citrate, catalyzed by citrate synthase.(wikipedia) A class of ketodicarboxylic acids derived from oxalic acid. Oxaloacetic acid is an intermediate in the citric acid cycle and is converted to aspartic acidD by a transamination reaction.

PW_C000149

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O-Phosphoethanolamine

Phosphoethanolamine (PE) is a phosphomonoester metabolite of the phospholipid metabolism. PE is a precursor of phospholipid synthesis and a product of phospholipid breakdown. Phosphomonoesters are present at much higher levels in brain than in other organs. In developing brain, phosphomonoesters are normally elevated during the period of neuritic proliferation. This also coincides with the occurrence of normal programmed cell death and synaptic pruning in developing brain. These findings are consistent with the role of phosphomonoesters in membrane biosynthesis. PE shows a strong structural similarity to the inhibitory neurotransmitter, GABA, and the GABAB receptor partial agonist, 3-amino-propylphosphonic acid. PE is a phosphomonoester which is decreased in post-mortem Alzheimer's disease (AD) brain. (PMID: 7791524, 8588821, 11566853).

PW_C000150

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Oxoadipic acid

2-Oxoadipic acid is produced from lysine in the cytosol of cells via the saccharopine and the pipecolic acid pathways. Catabolites of hydroxylysine and tryptophan enter these pathways as 2-aminoadipic-semialdehyde and 2-oxoadipate, respectively. In the mitochondrial matrix, 2-oxoadipate is decarboxylated to glutaryl-CoA by the 2-oxoadipate dehydrogenase complex and then converted into acetyl-CoA. Chronically high levels of oxoadipic acid are associated with at least two inborn errors of metabolism, including 2-aminoadipic aciduria and 2-oxoadipic aciduria. 2-Oxoadipic aciduria is an inborn error of metabolism involving lysine, tryptophan, and hydroxylysine, in which abnormal quantities of 2-aminoadipic acid are found in body fluids along with 2-oxoadipic acid. Patients with 2-oxoadipic acidemias are mentally retarded with hypotonia or seizures. 2-Oxoadipic aciduria can occur in patients with Kearns-Sayre syndrome, a progressive disorder with onset prior to 20 years of age in which multiple organ systems are affected. Affected individuals have progressive external ophthalmoplegia (PEO) and retinopathy, both of which are classically associated with abnormalities in cardiac conduction, cerebellar signs, and elevated cerebrospinal fluid protein (PMID: 10655159, 16183823, 11083877). When present in sufficiently high levels, oxoadipic acid can act as an acidogen and a metabotoxin. An acidogen is an acidic compound that induces acidosis, which has multiple adverse effects on many organ systems. A metabotoxin is an endogenously produced metabolite that causes adverse health effects at chronically high levels. Oxoadipic acid is an organic acid. Abnormally high levels of organic acids in the blood (organic acidemia), urine (organic aciduria), the brain, and other tissues lead to general metabolic acidosis. Acidosis typically occurs when arterial pH falls below 7.35. In infants with acidosis, the initial symptoms include poor feeding, vomiting, loss of appetite, weak muscle tone (hypotonia), and lack of energy (lethargy). These can progress to heart abnormalities, kidney abnormalities, liver damage, seizures, coma, and possibly death. These are also the characteristic symptoms of the untreated IEMs mentioned above. Many affected children with organic acidemias experience intellectual disability or delayed development. In adults, acidosis or acidemia is characterized by headaches, confusion, feeling tired, tremors, sleepiness, and seizures.

PW_C000151

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Orotic acid

Orotic acid is a minor dietary constituent. Indeed, until it was realized that it could be synthesized by humans, orotic acid was known as vitamin B-13. The richest dietary sources of orotic acid are cow's milk and other dairy products as well as root vegetables such as carrots and beets. Dietary intake probably contributes to a basal rate of orotic acid excretion in urine because fasting decreases excretion by ~50%. However, it is now apparent that most urinary orotic acid is synthesized in the body, where it arises as an intermediate in the pathway for the synthesis of pyrimidine nucleotides. Orotic acid is converted to UMP by UMP synthase, a multifunctional protein with both orotate phosphoribosyltransferase and orotidylate decarboxylase activity. The most frequently observed inborn error of pyrimidine nucleotide synthesis is a mutation of the multifunctional protein UMP synthase (UMP synthase deficiency or orotic aciduria). This disorder prevents the conversion of orotic acid to UMP, and thus to other pyrimidines. As a result, plasma orotic acid accumulates to high concentrations, and increased quantities appear in the urine. Indeed, urinary orotic acid is so markedly increased in individuals harboring a mutation in UMP synthase that orotic acid crystals can form in the urine. The urinary concentration of orotic acid in individuals suffering from orotic aciduria can be of the order of millimoles per millimole creatinine. By comparison, the urinary level in unaffected individuals is ~ 1 ┬Ámol/mmol creatinine (PMID: 17513443). Orotic aciduria is characterized by megaloblastic anemia and orotic acid crystalluria that is frequently associated with some degree of physical and mental retardation. These features respond to appropriate pyrimidine replacement therapy and most cases appear to have a good prognosis. When present in sufficiently high levels, orotic acid can act as an acidogen and a metabotoxin. An acidogen is an acidic compound that induces acidosis, which has multiple adverse effects on many organ systems. A metabotoxin is an endogenously produced metabolite that causes adverse health effects at chronically high levels. Chronically high levels of orotic acid are associated with at least seven inborn errors of metabolism, including argininemia, LPI syndrome (lysinuric protein intolerance), hyperornithinemia-hyperammonemia-homocitrullinuria (HHH), OTC deficiency, citrullinemia type I, purine nucleoside phosphorylase deficiency, and orotic aciduria. Orotic acid is an organic acid. Abnormally high levels of organic acids in the blood (organic acidemia), urine (organic aciduria), the brain, and other tissues lead to general metabolic acidosis. Acidosis typically occurs when arterial pH falls below 7.35. In infants with acidosis, the initial symptoms include poor feeding, vomiting, loss of appetite, weak muscle tone (hypotonia), and lack of energy (lethargy). These can progress to heart abnormalities, seizures, coma, and possibly death. These are also the characteristic symptoms of the untreated IEMs mentioned above. Many affected children with organic acidemias experience intellectual disability or delayed development. In adults, acidosis or acidemia is characterized by headaches, confusion, feeling tired, tremors, sleepiness, and seizures.

PW_C000152

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Mevalonic acid

Mevalonic acid is a key organic compound in biochemistry. It is a precursor in the biosynthetic pathway, known as the HMG-CoA reductase pathway, that produces terpenes and steroids. Mevalonate is produced by NADPH from 3-hydroxy-3-methylglutaryl CoA via reduction. This reaction occurs in the cytosol. It is the committed step in cholesterol synthesis, -- Wikipedia The production of mevalonic acid (MVA) by the enzyme 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, is the rate-limiting step in the biosynthesis of cholesterol. (Jemal et. al, Rapid Communications in Mass Spectrometry, 2003, 17:1715) Plasma concentrations and urinary excretion of MVA are decreased by HMG-CoA reductase inhibitor drugs such as pravastatin, simvastatin and atorvastatin. Naoumova RP, Marais AD, Mountney J, Firth JC, Rendell NB, Taylor GW, Thompson GR. Atherosclerosis 1996; 119: 203.

PW_C000153

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Phenol

Phenol, is a toxic, colourless crystalline solid with a sweet tarry odor that resembles a hospital smell. It is commonly used as an antiseptic and disinfectant. It is active against a wide range of micro-organisms including some fungi and viruses, but is only slowly effective against spores. It has been used to disinfect skin and to relieve itching. Phenol is also used in the preparation of cosmetics including sunscreens, hair dyes, and skin lightening preparations. It is also used in the production of drugs (it is the starting material in the industrial production of aspirin), weedkillers, and synthetic resins. Phenol can be found in areas with high levels of motor traffic, therefore, people living in crowded urban areas are frequently exposed to traffic-derived phenol vapor. The average (mean +/- SD) phenol concentration in urine among normal individuals living in urban areas is 7.4 +/- 2.2 mg/g of creatinine. Exposure of the skin to concentrated phenol solutions causes chemical burns which may be severe; in laboratories where it is used, it is usually recommended that polyethylene glycol solution is kept available for washing off splashes. Notwithstanding the effects of concentrated solutions, it is also used in cosmetic surgery as an exfoliant, to remove layers of dead skin (Wikipedia). In some bacteria phenol can be directly synthesized from tyrosine via the enzyme tyrosine phenol-lyase [EC:4.1.99.2].

PW_C000154

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Nicotinamide ribotide

Nicotinamide ribotide (NMN) is an important intermediate metabolite in the nicotinate and nicotinamide metabolism pathway. Mammals predominantly use nicotinamide rather than nicotinic acid as a precursor for NAD biosynthesis. Instead of the deamidation to nicotinic acid, nicotinamide is directly converted to NMN by nicotinamide phosphoribosyltransferase (NAMPT, EC 2.4.2.12). The enzyme nicotinamide mononucleotide adenylyltransferase (NMNAT, EC 2.7.7.1), which is a member of the nucleotidyltransferase alpha/beta-phosphodiesterase superfamily, catalyzes the reaction NMN + ATP <=> Nicotinamide adenine dinucleotide (NAD) + PPi, representing the final step in the biosynthesis of NAD. NAD is a molecule that plays a fundamental role as a cofactor in cellular redox reactions. Thus NMN is an important metabolite for the maintenance of normal NAD biosynthesis. Circulating NMN levels may play an important role in regulating cell function in physiological and pathophysiological conditions. (PMID: 15078171, 17983582).

PW_C000155

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N-Acetylneuraminic acid

N-Acetylneuraminic acid (NeuAc) or sialic acid is an acetyl derivative of the amino sugar neuraminic acid. It occurs in many glycoproteins, glycolipids, and polysaccharides in both mammals and bacteria. The most abundant sialic acid, NeuAc, is synthesized in vivo from N-acetylated D-mannosamine (ManNAc) or D-glucosamine (GlcNAc). NeuAc and its activated form, CMP-NeuAc, are biosynthesized in five consecutive reactions: UDP-N-acetylglucosamine (UDP-GlcNAc) N-acetylmannosamine (ManNAc) ManNAc 6-phosphate NeuAc 9-phosphate NeuAc CMP-NeuAc. CMP-NeuAc is transported into the Golgi apparatus and, with the aid of specific sialyltransferases, added onto nonreducing positions on oligosaccharide chains of glycoproteins and glycolipids. NeuAc is widely distributed throughout human tissues and found in several fluids, including serum, cerebrospinal fluid, saliva, urine, amniotic fluid, and breast milk. It is found in high levels in the brain, adrenal glands, and the heart. Serum and urine levels of the free acid are elevated in individuals suffering from renal failure. Serum and saliva Neu5Ac levels are also elevated in alcoholics. A disorder known as Salla disease or infantile NeuAc storage disease is also characterized by high serum and urine levels of this compound. The negative charge of is responsible for the slippery feel of saliva and mucins coating the body's organs. This particular sialic acid is known to act as a "decoy" for invading pathogens. Along with involvement in preventing infections (mucus associated with mucous membranes mouth, nose, GI, respiratory tract), Neu5Ac acts as a receptor for influenza viruses, allowing attachment to mucous cells via hemagglutinin (an early step in acquiring influenzavirus infection). NeuAc is also becoming known as an agent necessary for mediating ganglioside distribution and structures in the brain. Sialic acid (SA) is an N-acetylated derivative of neuraminic acid that is an abundant terminal monosaccharide of glycoconjugates. Normal human serum SA is largely bound to glycoproteins or glycolipids (Total sialic acid, TSA, 1.5-2.5 mmol/L), with small amounts of free SA (1-3 umol/L). Negatively charged SA units stabilize glycoprotein conformation in cell surface receptors to increase cell rigidity. This enables signal recognition and adhesion to ligands, antibodies, enzymes and microbes. SA residues are antigenic determinant residues in carbohydrate chains of glycolipids and glycoproteins, chemical messengers in tissue and body fluids, and may regulate glomeruli basement membrane permeability. Sialic acids are structurally unique nine-carbon keto sugars occupying the interface between the host and commensal or pathogenic microorganisms. An important function of host sialic acid is to regulate innate immunity. Sialic acid is the moiety most actively recycled for metabolic purposes in the salvage pathways in glycosphingolipid metabolism. Sialic acid is indispensable for the neuritogenic activities of gangliosides constituents which are unique in that a sialic acid directly binds to the glucose of the cerebroside, they are mutually connected in tandem, and some are located in the internal parts of the sugar chain. Sialylation (sialic acid linked to galactose, N-acetylgalactosamine, or linked to another sialic acid) represents one of the most frequently occurring terminations of the oligosaccharide chains of glycoproteins and glycolipids. The biosynthesis of the various linkages is mediated by the different members of the sialyltransferase family. (PMID: 11425186 , 11287396 , 12770781 , 16624269 , 12510390 , 15007099 ).

PW_C000156

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Quinolinic acid

Quinolinic acid is a metabolite of tryptophan with a possible role in neurodegenerative disorders. Elevated CSF levels of quinolinic acid are correlated with the severity of neuropsychological deficits in patients who have AIDS. Quinolinic acid (QUIN) is a product of tryptophan metabolism that can act as an endogenous brain excitotoxin when released by activated macrophages. (Valle et. al, Brain 127:1047 (2004)).

PW_C000157

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Testosterone

Testosterone is the most important androgen in potency and quantity. Testosterone is synthesized and released by the Leydig cells that lie between the tubules and comprise less than 5% of the total testicular volume. testosterone diffuses into the seminiferous tubules where it is essential for maintaining spermatogenesis. Some binds to an androgen-binding protein (ABP) that is produced by the Sertoli cells and is homologous to the sex-hormone binding globulin that transports testosterone in the general circulation. The ABP carries testosterone in the testicular fluid where it maintains the activity of the accessory sex glands and may also help to retain testosterone within the tubule and bind excess free hormone. Some testosterone is converted to estradiol by Sertoli cell-derived aromatase enzyme. Leydig cell steroidogenesis is controlled primarily by luteinizing hormone with negative feedback of testosterone on the hypothalamic-pituitary axis. The requirement of spermatogenesis for high local concentrations of testosterone means that loss of androgen production is likely to be accompanied by loss of spermatogenesis. Indeed, if testicular androgen production is inhibited by the administration of exogenous androgens then spermatogenesis ceases. This is the basis of using exogenous testosterone as a male contraceptive. testosterone is converted to dihydrotestosterone by 5a-reductase type 2 (EC 1.3.1.22, SRD5A2), the androgen with the highest affinity for the androgen receptor. SRD5A2 deficiency illustrates the importance of dihydrotestosterone for external virilization, as individuals with this condition have normal male internal structures but their external genitalia are of female appearance. There is now clear evidence that the human fetal testis and also the fetal adrenal gland is capable of testosterone biosynthesis during the first trimester. Regardless of the source of androgen production, the target tissue responds by male sexual differentiation of the external genitalia by the end of the first trimester. It is clear that testicular damage may result in loss of testosterone production or the loss of spermatogenesis or both. Loss of androgen production results in hypogonadism, the symptoms of which reflect the functions of testosterone. Male hypogonadism is defined as failure of the testes to produce normal amounts of testosterone, combined with signs and symptoms of androgen deficiency. Systemic testosterone levels fall by about 1% each year in men. Therefore, with increasing longevity and the aging of the population, the number of older men with testosterone deficiency will increase substantially over the next several decades. Serum testosterone levels decrease progressively in aging men, but the rate and magnitude of decrease vary considerably. Approximately 1% of healthy young men have total serum testosterone levels below normal; in contrast, approximately 20% of healthy men over age 60 years have serum testosterone levels below normal. (PMID: 17904450, 17875487).

PW_C000158

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Thiamine

Thiamine or thiamin, also known as vitamin B1, is a colorless compound with the chemical formula C12H17N4OS. It is soluble in water and insoluble in alcohol. Thiamine decomposes if heated. Thiamine was first discovered by Umetaro Suzuki in Japan when researching how rice bran cured patients of Beriberi. Thiamine plays a key role in intracellular glucose metabolism and it is thought that thiamine inhibits the effect of glucose and insulin on arterial smooth muscle cell proliferation. thiamine plays an important role in helping the body convert carbohydrates and fat into energy. It is essential for normal growth and development and helps to maintain proper functioning of the heart and the nervous and digestive systems. Thiamine cannot be stored in the body; however, once absorbed, the vitamin is concentrated in muscle tissue.

PW_C000159

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Propionic acid

Propionic acid (PA) is widely used as an antifungal agent in food. It is present naturally at low levels in dairy products and occurs ubiquitously, together with other short-chain fatty acids (SCFA), in the gastro-intestinal tract of humans and other mammals as an end-product of the microbial digestion of carbohydrates. It has significant physiological activity in animals. PA is irritant but produces no acute systemic effects and has no demonstrable genotoxic potential. (PMID 1628870) Propionic aciduria is one of the most frequent organic acidurias, a disease that comprise many various disorders. The outcome of patients born with Propionic aciduria is poor intellectual development patterns, with 60% having an IQ less than 75 and requiring special education. Successful liver and/or renal transplantations, in a few patients, have resulted in better quality of life but have not necessarily prevented neurological and various visceral complications. These results emphasize the need for permanent metabolic follow-up whatever the therapeutic strategy. (PMID 15868474) Decreased early mortality, less severe symptoms at diagnosis, and more favorable short-term neurodevelopmental outcome were recorded in patients identified through expanded newborn screening. (PMID 16763906).

PW_C000160

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Sepiapterin

Sepiapterin, also known as lopac-S-154, belongs to the class of organic compounds known as pterins and derivatives. These are polycyclic aromatic compounds containing a pterin moiety, which consist of a pteridine ring bearing a ketone and an amine group to form 2-aminopteridin-4(3H)-one. Sepiapterin is slightly soluble (in water) and a very weakly acidic compound (based on its pKa). Sepiapterin has been primarily detected in cerebrospinal fluid. Within the cell, sepiapterin is primarily located in the cytoplasm and mitochondria. In humans, sepiapterin is involved in pterine biosynthesis pathway. Sepiapterin is also involved in several metabolic disorders, some of which include sepiapterin reductase deficiency, hyperphenylalaninemia due to DHPR-deficiency, hyperphenylalaninemia due to 6-pyruvoyltetrahydropterin synthase deficiency (PTPS), and the dopa-responsive dystonia pathway. Sepiapterin is an intermediate in the salvage pathway of tetrahydrobiopterin (BH(4)). It is a yellow fluorescing pigment. Sepiapterin accumulates in the brain of patients with sepiapterin reductase (SR) deficiency.

PW_C000161

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Pyridoxine

The 4-methanol form of vitamin B6 which is converted to pyridoxal phosphate which is a coenzyme for synthesis of amino acids, neurotransmitters (serotonin, norepinephrine), sphingolipids, aminolevulinic acid. Although pyridoxine and Vitamin B6 are still frequently used as synonyms, especially by medical researchers, this practice is erroneous and sometimes misleading (EE Snell; Ann NY Acad Sci, vol 585 pg 1, 1990). Pyridoxine is one of the compounds that can be called vitamin B6. Pyridoxine assists in the balancing of sodium and potassium as well as promoting red blood cell production. It is linked to cancer immunity and helps fight the formation of homocysteine. It has been suggested that Pyridoxine might help children with learning difficulties, and may also prevent dandruff, eczema, and psoriasis. In addition, pyridoxine can help balance hormonal changes in women and aid in immune system. Lack of pyridoxine may cause anemia, nerve damage, seizures, skin problems, and sores in the mouth. -- Wikipedia Deficiency, though rare because of widespread distribution in foods, leads to the development of peripheral neuritis in adults and affects the central nervous system in children (DOSE - 3rd edition).

PW_C000162

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Sulfite

Endogenous sulfite is generated as a consequence of the body's normal processing of sulfur-containing amino acids. Sulfites occur as a consequence of fermentation and also occur naturally in a number of foods and beverages. As food additives, sulfiting agents were first used in 1664 and have been approved in the United States since the 1800s. Sulfite is an allergen, a neurotoxin, and a metabotoxin. An allergen is a compound that causes allergic reactions such as wheezing, rash, or rhinitis. A neurotoxin is a substance that causes damage to nerves or brain tissues. A metabotoxin is an endogenously produced metabolite that causes adverse health effects at chronically high levels. As an allergen, sulfite is known to induce asthmatic reactions. Sulfite sensitivity occurs most often in asthmatic adults (predominantly women), but it is also occasionally reported in preschool children. Adverse reactions to sulfites in nonasthmatics are extremely rare. Asthmatics who are steroid-dependent or who have a higher degree of airway hyperreactivity may be at greater risk of experiencing a reaction to sulfite-containing foods. Sulfite sensitivity reactions vary widely, ranging from no reaction to severe. The majority of reactions are mild. These manifestations may include dermatologic, respiratory, or gastrointestinal signs and symptoms. The precise mechanisms of the sensitivity responses have not been completely elucidated: inhalation of sulfur dioxide (SO2) generated in the stomach following ingestion of sulfite-containing foods or beverages, a deficiency in a mitochondrial enzyme, and an IgE-mediated immune response have all been implicated. Exogenously supplied sulfite is detoxified by the enzyme sulfite oxidase. Sulfite oxidase (EC 1.8.3.1) is 1 of 3 enzymes in humans that require molybdenum as a cofactor. Under certain circumstances, chronically high levels of sulfite can lead to serious neurotoxicity. Sulfite oxidase deficiency (also called molybdenum cofactor deficiency) is a rare autosomal inherited disease that is typified by high concentrations of sulfite in the blood and urine. It is characterized by severe neurological symptoms such as untreatable seizures, attenuated growth of the brain, and mental retardation. It results from defects in the enzyme sulfite oxidase, which is responsible for the oxidation of sulfite to sulfate. This sulfite to sulfate reaction is the final step in the degradation of sulfur-containing metabolites (including the amino acids cysteine and methionine). The term "isolated sulfite oxidase deficiency" is used to define the deficiency caused by mutations in the sulfite oxidase gene. This differentiates it from another version of sulfite oxidase deficiency that is due to defects in the molybdenum cofactor biosynthetic pathway (with mutations in the MOCS1 or MOCS2 genes). Isolated sulfite oxidase deficiency is a rare but devastating neurologic disease that usually presents in early infancy with seizures and alterations in muscle tone (PMID: 16234925, 16140720, 8586770). Sulfite oxidase deficiency (as caused by MOCS1 or MOCS2) may be treated with cPMP, a precursor of the molybdenum cofactor (PMID: 20385644). The mechanism behind sulfite neurotoxicity appears to be related to its ability to bind and inhibit glutamate dehydrogenase (GDH). Inhibition of GDH leads to a decrease in alpha-ketoglutarate and a diminished flux through the tricarboxylic acid cycle. This is accompanied by a decrease in NADH through the mitochondrial electron transport chain, which leads to a decrease in mitochondrial membrane potential and in ATP synthesis. Since glutamate is a major metabolite in the brain, inhibition of GDH by sulfite appears to contribute to neural damage characteristic of sulfite oxidase deficiency in human infants (PMID: 15273247).

PW_C000163

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Protoporphyrin IX

Protoporphyrins are tetrapyrroles containing 4 methyl, 2 propionic, and 2 vinyl side chains. Protoporphyrin is produced by oxidation of the methylene bridge of protoporphyrinogen. Protoporphyrin IX is the only naturally occurring isomer; it is an intermediate in heme biosynthesis, combining with ferrous iron to form protoheme IX, the heme prosthetic group of hemoglobin. Protoporphyrin IX is created by the enzyme protoporphyrinogen oxidase. The enzyme ferrochelatase converts it into heme. Protoporphyrin IX naturally occurs in small amounts in feces. Protoporphyrin IX is also responsible for the brown pigment (ooporphyrin) of birds' eggs. Protoporphyrin IX is used as a branch point in the biosynthetic pathway leading to heme (by insertion of iron) and chlorophylls (by insertion of Mg and further side-chain transformation). Protoporphyrin IX can be used to treat liver disorders, mainly as the sodium salt. Under certain conditions, protoporphyrin IX can act as a neurotoxin, a phototoxin, and a metabotoxin. A neurotoxin causes damage to nerve cells and nerve tissues. A phototoxin causes cell damage upon exposure to light. A metabotoxin is an endogenously produced metabolite that causes adverse health effects at chronically high levels. Chronically high levels of porphyrins are associated with porphyrias such as porphyria variegate, acute intermittent porphyria, and hereditary coproporphyria (HCP). In particular, it is accumulated and excreted excessively in the feces in acute intermittent porphyria, protoporphyria, and variegate porphyria. There are several types of porphyrias (most are inherited). Hepatic porphyrias are characterized by acute neurological attacks (seizures, psychosis, extreme back and abdominal pain, and an acute polyneuropathy), while the erythropoietic forms present with skin problems (usually a light-sensitive blistering rash and increased hair growth). The neurotoxicity of porphyrins may be due to their selective interactions with tubulin, which disrupt microtubule formation and cause neural malformations (PMID: 3441503).

PW_C000164

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Pyruvic acid

Pyruvic acid is an intermediate compound in the metabolism of carbohydrates, proteins, and fats. In thiamine deficiency, its oxidation is retarded and it accumulates in the tissues, especially in nervous structures. (From Stedman, 26th ed.) Biological Source: Intermediate in primary metabolism including fermentation processes. Present in muscle in redox equilibrium with Lactic acid. A common constituent, as a chiral cyclic acetal linked to saccharide residues, of bacterial polysaccharides. Isolated from cane sugar fermentation broth and peppermint. Constituent of Bauhinia purpurea, Cicer arietinum (chickpea), Delonix regia, Pisum sativum (pea) and Trigonella caerulea (sweet trefoil) Use/Importance: Reagent for regeneration of carbonyl compdounds from semicarbazones, phenylhydrazones and oximes. Flavoring ingredient (Dictionary of Organic Compounds).

PW_C000165

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Riboflavin

Riboflavin or vitamin B2 is an easily absorbed, water-soluble micronutrient with a key role in maintaining human health. Like the other B vitamins, it supports energy production by aiding in the metabolizing of fats, carbohydrates, and proteins. Vitamin B2 is also required for red blood cell formation and respiration, antibody production, and for regulating human growth and reproduction. It is essential for healthy skin, nails, hair growth and general good health, including regulating thyroid activity. Riboflavin is found in milk, eggs, malted barley, liver, kidney, heart, and leafy vegetables. Riboflavin is yellow or orange-yellow in color and in addition to being used as a food coloring it is also used to fortify some foods. It can be found in baby foods, breakfast cereals, sauces, processed cheese, fruit drinks and vitamin-enriched milk products. The richest natural source is yeast. It occurs in the free form only in the retina of the eye, in whey, and in urine; its principal forms in tissues and cells are as flavin mononucleotide and flavin adenine dinucleotide.

PW_C000166

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Porphobilinogen

Porphobilinogen (PBG) is a pyrrole-containing intermediate in the biosynthesis of porphyrins. It is generated from aminolevulinate (ALA) by the enzyme ALA dehydratase. Porphobilinogen is then converted into hydroxymethylbilane by the enzyme porphobilinogen deaminase (also known as hydroxymethylbilane synthase). Under certain conditions, porphobilinogen can act as a phototoxin, a neurotoxin, and a metabotoxin. A phototoxin leads to cell damage upon exposure to light. A neurotoxin causes damage to nerve cells and nerve tissues. A metabotoxin is an endogenously produced metabolite that causes adverse health effects at chronically high levels. Chronically high levels of porphyrins are associated with porphyrias such as porphyria variegate, acute intermittent porphyria, and hereditary coproporphyria (HCP). There are several types of porphyrias (most are inherited). Hepatic porphyrias are characterized by acute neurological attacks (seizures, psychosis, extreme back and abdominal pain, and an acute polyneuropathy), while the erythropoietic forms present with skin problems (usually a light-sensitive blistering rash and increased hair growth). The neurotoxicity of porphyrins may be due to their selective interactions with tubulin, which disrupt microtubule formation and cause neural malformations (PMID: 3441503).

PW_C000168

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Sorbitol

Sorbitol is a polyhydric alcohol with about half the sweetness of sucrose. Sorbitol occurs naturally and is also produced synthetically from glucose. It was formerly used as a diuretic and may still be used as a laxative and in irrigating solutions for some surgical procedures. It is also used in many manufacturing processes, as a pharmaceutical aid, and in several research applications. Ascorbic acid fermentation; in solution form for moisture-conditioning of cosmetic creams and lotions, toothpaste, tobacco, gelatin; bodying agent for paper, textiles, and liquid pharmaceuticals; softener for candy; sugar crystallization inhibitor; surfactants; urethane resins and rigid foams; plasticizer, stabilizer for vinyl resins; food additive (sweetener, humectant, emulsifier, thickener, anticaking agent); dietary supplement. (Hawley's Condensed Chemical Dictionary) Biological Source: Occurs widely in plants ranging from algae to the higher orders. Fruits of the plant family Rosaceae, which include apples, pears, cherries, apricots, contain appreciable amounts. Rich sources are the fruits of the Sorbus and Crataegus species Use/Importance: Used for manufacturing of sorbose, propylene glycol, ascorbic acid, resins, plasticizers and as antifreeze mixtures with glycerol or glycol. Tablet diluent, sweetening agent and humectant, other food uses. Sorbitol is used in photometric determination of Ru(VI) and Ru(VIII); in acid-base titration of borate (Dictionary of Organic Compounds).
Showing 141 - 160 of 78500 compounds