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Taurine
From Wikipedia, the free encyclopedia
| Taurine | |
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| IUPAC name | Taurine |
| Molecular formula | C2H7NO3S |
| Identifiers | |
| CAS number | [] |
| SMILES | NCCS(=O)(O)=O |
| Properties | |
| Molar mass | 125.14 g/mol |
| Density | 1.734 g/cm³ (at -173.15 °C) |
| Melting point |
305.11 °C |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Taurine or 2-aminoethanesulfonic acid is an organic acid that is abundant in the tissues of many animals (metazoa).[1] Taurine is also found in plants, fungi, and some bacterial species, but at lower levels. Taurine is a derivative of the sulphur-containing (sulfhydryl) amino acid, cysteine.
Taurine is named after the Latin taurus, which means bull, as it was first isolated from ox (Bos taurus) bile as well as semen in 1827 by Austrian scientists Friedrich Tiedemann and Leopold Gmelin. It is often called an amino acid, even in scientific literature,[2][3][4] but it lacks a carboxyl group and therefore does not qualify as an amino acid.[5] It does contain a sulfonate group and may be called an amino sulfonic acid. Small polypeptides have been identified which contain taurine but to date no aminoacyl tRNA synthetase has been identified as specifically recognizing taurine and capable of charging it onto a tRNA.[6]
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The major pathway for mammalian taurine synthesis occurs in the liver via the cysteine sulfinic acid pathway. In this pathway, the sulfhydryl group of cysteine is first oxidized to cysteine sulfinic acid by the enzyme cysteine dioxygenase. Cysteine sulfinic acid, in turn, is decarboxylated by Sulfinoalanine decarboxylase (EC 4.1.1.27) to form hypotaurine. It is unclear whether hypotaurine is then spontaneously or enzymatically oxidized to yield taurine.
Taurine in the pharmaceutical and lab setting is synthesized through a combination of cysteine, methionine and vitamin E.
Urban legends surrounding the source of taurine have included bull urine extract and bull semen. While it's true that taurine is found in both sources, it is not the source of taurine in the pharmaceutical or food industry.
Taurine is conjugated via its amino terminal group with the bile acids chenodeoxycholic acid and cholic acid to form the bile salts sodium taurochenodeoxycholate and sodium taurocholate (see bile). The low pKa (1.5) of taurine's sulfonic acid group ensures that this moiety is negatively charged in the pH ranges normally found in the intestinal tract and thus improves the surfactant properties of the cholic acid conjugate.
Taurine has also been implicated in a wide array of other physiological phenomena including inhibitory neurotransmission, long-term potentiation in the striatum/hippocampus, membrane stabilization, feedback inhibition of neutrophil/macrophage respiratory bursts, adipose tissue regulation, and calcium homeostasis. The evidence for these claims, when compared against that reported for taurine's role in bile acid synthesis and osmoregulation, is relatively poor.
Prematurely born infants who lack the enzymes needed to convert cystathionine to cysteine may become deficient in taurine. Thus, taurine is a dietary essential nutrient in these individuals and is often added to many infant formulas as a measure of prudence. There is also evidence that taurine in adult humans reduces blood pressure.[7]
Many therapeutic applications of taurine have been investigated. Conditions that taurine might be useful in treating include: cardiovascular diseases, hypercholesterolemia, epilepsy, and other seizure disorders, macular degeneration, Alzheimer's disease, hepatic disorders, alcoholism, and cystic fibrosis.[8]
Anxiety disease/panic disorder also show signs of amelioration.[citation needed] If taurine is going to work, it works almost immediately.[citation needed] Recent studies show that taurine supplements taken by mice on a high-fat diet reduced their overall weight. Studies have yet to be done on the effect of taurine on obesity in humans.[9]. Recent studies have also shown that taurine can influence (and possibly reverse) nerve blood flow, motor nerve conduction velocity, and nerve sensory threshold defects in experimental diabetic neuropathic rats.[10][11] Taurine levels were found to be significantly lower in vegans than in a control group on a standard American diet. Plasma taurine was 78% of control values, and urinary taurine 29%.[12] In recent years, taurine has become a common ingredient in energy drinks. Taurine is also often used in combination with bodybuilding supplements such as creatine and anabolic steroids. Taurine is also used in some contact lens solutions. Taurine has also been shown in diabetic rats to decrease weight and decrease blood sugar.[13]
Taurine is essential for cat health, as a cat cannot synthesize the compound. The absence of taurine causes a cat's retina to slowly degenerate, causing eye problems and (eventually) irreversible blindness. This condition is called central retinal degeneration (CRD).[14][15] In addition, taurine deficiency can cause feline dilated cardiomyopathy, and supplementation can reverse left ventricular systolic dysfunction. (Pion et al 1988) Taurine is now a requirement of the AAFCO and any dry or wet food product labeled approved by the AAFCO should have a minimum of .1% Taurine. For further AAFCO requirements for cats, consult the table here.
Usage above 28.57 PPM in non-alcoholic beverages is deemed non-GRAS as determined by Flavor and Extract Manufacturers Association (FEMA) Expert Panel. A typical energy drink that contains 1 mg of taurine corresponds to a concentration of about 4.083 ppm.
Taurine is an ingredient in many energy drinks and energy products; in fact, it is from this ingredient that Red Bull gets its name. It is present in the alcoholic drinks Sparks and Spykes. It is also found as an additive in no-rub contact lens fluids. It is in Foosh Energy Mints and Buzz Bites Chocolate Energy Chews.
- ^ Brosnan J, Brosnan M (2006). "The sulfur-containing amino acids: an overview.". J Nutr 136 (6 Suppl): 1636S-1640S. PMID 16702333.
- ^ Stapleton, PP; L O'Flaherty, HP Redmond, and DJ Bouchier-Hayes (1998). "Host defense--a role for the amino acid taurine?". Journal of Parenteral and Enteral Nutrition 22 (1): 42–48. Retrieved on 2006-08-19.
- ^ Weiss, Stephen J.; Roger Klein, Adam Slivka, and Maria Wei (1982). "Chlorination of Taurine by Human Neutrophils". Journal of Clinical Investigation 70 (3): 598–607. Retrieved on 2006-08-19.
- ^ Kirk, Kiaran; and Julie Kirk (1993). "Volume-regulatory taurine release from a human lung cancer cell line". FEBS Letters 336 (1): 153–158. DOI:doi:10.1016/0014-5793(93)81630-I.
- ^ Carey, Francis A. [1987] (2006). Organic Chemistry, 6th ed., New York: McGraw Hill, 1149. ISBN 0-07-282837-4. “Amino acids are carboxylic acids that contain an amine function.”
- ^ Lahdesmaki, P (1987). "Biosynthesis of taurine peptides in brain cytoplasmic fraction in vitro.". Int J Neuroscience 37 (1-2): 79–84.
- ^ Militante, J. D.; J. B. Lombardini (November 2002). "Treatment of hypertension with oral taurine: experimental and clinical studies". Amino Acids 23 (4): 381–393. DOI:10.1007/s00726-002-0212-0. Retrieved on 2006-08-22.
- ^ Birdsall, Timothy C.. Therapeutic Applications of Taurine. Retrieved on 2006-08-22.
- ^ Currently taurine is being tested as an anti-manic treatment for bipolar depression. Tsuboyama-Kasaoka, Nobuyo; Chikako Shozawa, Kayo Sano, Yasutomi Kamei, Seiichi Kasaoka, Yu Hosokawa and Osamu Ezaki (2006). "Taurine (2-Aminoethanesulfonic Acid) Deficiency Creates a Vicious Circle Promoting Obesity". Endocrinology 147 (7): 3276–3284. DOI:10.1210/en.2005-1007. Retrieved on 2006-08-22.
- ^ Li F, Abatan OI, Kim H, Burnett D, Larkin D, Obrosova IG, Stevens MJ (2006 Jun). "Taurine reverses neurological and neurovascular deficits in Zucker diabetic fatty rats.". Neurobiology of Disease 22 (3).
- ^ Pop-Busui R, Sullivan KA, Van Huysen C, Bayer L, Cao X, Towns R, Stevens MJ (2001 Apr). "Depletion of taurine in experimental diabetic neuropathy: implications for nerve metabolic, vascular, and functional deficits.". Exp Neurol. 168 (2).
- ^ Laidlaw S, Shultz T, Cecchino J, Kopple J (1988) "Plasma and urine taurine levels in vegans." American Journal of Clinical Nutrition, vol. 47, pp. 660-663.
- ^ "Taurine improves insulin sensitivity in the Otsuka Long-Evans Tokushima Fatty rat, a model of spontaneous type 2 diabetes". American Journal of Clinical Nutrition Vol. 71 (No. 1): 54-58.
- ^ Taurine And Its Importance In Cat Foods. Iams Cat Nutrition Library (2004). Retrieved on 2006-08-22.
- ^ Nutrient Requirements of Cats. Nutrient Requirements of Cats, Revised Edition, 1986 (1986). Retrieved on 2006-09-10.