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Taurine



Taurine
IUPAC name Taurine
Molecular formula C2H7NO3S
Identifiers
CAS number 107-35-7
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

Taurine, or 2-aminoethanesulfonic acid, is an organic acid. It is also a major constituent of bile, and can be found in lower amounts in the tissues of many animals including humans. [1][2] Taurine is a derivative of the sulfur-containing (sulfhydryl) amino acid, cysteine. Taurine is the only known naturally occurring sulfonic acid.[3]

Taurine is named after the Latin taurus, which means bull or ox, as it was first isolated from ox bile in 1827 by Austrian scientists Friedrich Tiedemann and Leopold Gmelin. It is often called an amino acid, even in scientific literature,[4][5][6] but as it lacks a carboxyl group it is not strictly an amino acid.[7] 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 incorporating it onto a tRNA.[8]

Additional recommended knowledge

Contents

Physiological roles

Taurine is conjugated via its amino terminal group with its 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,[9] long-term potentiation in the striatum/hippocampus, membrane stabilization, feedback inhibition of neutrophil/macrophage respiratory bursts, adipose tissue regulation, and calcium homeostasis.

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.[10]

Obese mice demonstrate reduced blood levels of taurine, which may promote further weight gain, and taurine supplementation prevented obesity in mice fed a high-fat, low-taurine diet.[11] Recent studies have also shown that taurine can influence (and possibly reverse) defects in nerve blood flow, motor nerve conduction velocity, and nerve sensory thresholds in experimental diabetic neuropathic rats.[12][13] 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%.[14]

According to some animal studies, taurine produced an anxiolytic-like effect in mice and may act as a modulator or anti-anxiety agent in the central nervous system.[15]

In recent years, taurine has become a common ingredient in energy drinks. Taurine is often used in combination with bodybuilding supplements such as creatine and anabolic steroids, partly due to recent findings in mice that taurine alleviates muscle fatigue in strenuous workouts and raises exercise capacity.[16] Taurine is also used in some contact lens solutions.[citation needed]

Taurine has also been shown in diabetic rats to decrease weight and decrease blood sugar.[17]

Taurine and cats

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).[18][19] In addition, taurine deficiency can cause feline dilated cardiomyopathy, and supplementation can reverse left ventricular systolic dysfunction. However, the vegetarian lioness Little Tyke survived for years in captivity without imbibing the normal required dose of taurine.[20][21] 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 0.1% taurine.[22]

Synthesis and Production

In 1993, approximately 5,000–6,000 t of taurine (synthetic and natural) were produced; 50% for pet food manufacture, 50% in pharmaceutical applications.[3] Synthetic taurine is obtained from isethionic acid (2-hydroxyethanesulfonic acid), which in turn is obtained from the reaction of ethylene oxide with aqueous sodium bisulfite.[23] Another approach is the reaction of aziridine with sulfurous acid. This leads directly to taurine.

Energy drinks

Taurine is an ingredient in many energy drinks and energy products.

Energy Drink (not comprehensive list) Taurine concentration Normalized concentration
Full Throttle 1194 mg/16 oz (2 servings) 263.2 mg/100g
Monster 2000 mg/16 oz (2 servings) 440.9 mg/100g
NOS 1000 mg/8 oz (1 serving) 440.9 mg/100g
Red Bull 1000 mg/8.3 oz (1 serving) 425 mg/100g
Rip It 1000 mg/8 oz (1 serving) 440.9 mg/100g
Rockstar 2000 mg/16 oz (2 servings) 440.9 mg/100g
SoBe No Fear 2000 mg/16 oz (2 servings) 440.9 mg/100g
V 473 mg/8 oz 208.6 mg/100g
Vitamin Water Power C Dragon Fruit Flavor 25 mg/24 fl oz (2.5 servings)
Von Dutch 1.6 mg/100g (1/5 of a can) 2000 mg/16 oz (2 servings) 440.9 mg/100g

Despite its presence in many energy drinks, taurine has not been shown to be energy-giving. A study of mice hereditarily unable to transport taurine suggests that it is needed for proper maintenance and functioning of skeletal muscles.[24]

References

  1. ^ Bouckenooghe T, Remacle C, Reusens B (2006). "Is taurine a functional nutrient?". Curr Opin Clin Nutr 9 (6): 728-733.
  2. ^ Brosnan J, buffalo bill Brosnan M (2006). "The sulfur-containing amino acids: an overview.". J Nutr 136 (6 Suppl): 1636S-1640S. PMID 16702333.
  3. ^ a b Tully, Paul S. Sulfonic Acids. In Kirk-Othmer Encyclopedia of Chemical Technology. John Wiley & Sons, Inc. Published online 2000. doi:10.1002/0471238961.1921120620211212.a01
  4. ^ 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.
  5. ^ 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.
  6. ^ Kirk, Kiaran; and Julie Kirk (1993). "Volume-regulatory taurine release from a human heart cancer cell line". FEBS Letters 336 (1): 153–158. doi:10.1016/0014-5793(93)81630-I.
  7. ^ 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.” 
  8. ^ Lahdesmaki, P (1987). "Biosynthesis of taurine peptides in brain cytoplasmic fraction in vitro.". Int J Neuroscience 37 (1-2): 79–84.
  9. ^ Olive MF. Interactions between taurine and ethanol in the central nervous system. Amino Acids 2002;23(4):345-57
  10. ^ 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.
  11. ^ 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.
  12. ^ 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). PMID 16624563.
  13. ^ 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). PMID 11259114.
  14. ^ 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.
  15. ^ Kong WX, Chen SW, Li YL, et al (2006). "Effects of taurine on rat behaviors in three anxiety models". Pharmacol. Biochem. Behav. 83 (2): 271–6. doi:10.1016/j.pbb.2006.02.007. PMID 16540157.
  16. ^ U. Warskulat, U. Flogel, C. Jacoby, H.-G. Hartwig, M. Thewissen, M. W. Merx, A. Molojavyi, B. Heller-Stilb, J. Schrader and D. Haussinger (2004). "Taurine transporter knockout depletes muscle taurine levels and results in severe skeletal muscle impairment but leaves cardiac function uncompromised". FASEB J.: 03-0496fje. doi:10.1096/fj.03-0496fje.
  17. ^ "Taurine improves insulin sensitivity in the Otsuka Long-Evans Tokushima Fatty rat, a model of spontaneous type 2 diabetes". American Journal of Clinical Nutrition 71 (1): 54-58.
  18. ^ Taurine And Its Importance In Cat Foods. Iams Cat Nutrition Library (2004). Retrieved on 2006-08-22.
  19. ^ Nutrient Requirements of Cats. Nutrient Requirements of Cats, Revised Edition, 1986 (1986). Retrieved on 2006-09-10.
  20. ^ The Vegetarian Lioness.
  21. ^ Pion et al 1988
  22. ^ AAFCO
  23. ^ Kurt Kosswig. Sulfonic Acids, Aliphatic. in Ullmann's Encyclopedia of Industrial Chemistry. Wiley-VCH, 2000. doi:10.1002/14356007.a25_503
  24. ^ U. Warskulat, U. Flogel, C. Jacoby, H.-G. Hartwig, M. Thewissen, M. W. Merx, A. Molojavyi, B. Heller-Stilb, J. Schrader and D. Haussinger (2004). "Taurine transporter knockout depletes muscle taurine levels and results in severe skeletal muscle impairment but leaves cardiac function uncompromised". FASEB J.: 03-0496fje. doi:10.1096/fj.03-0496fje. PMID 14734644.
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Taurine". A list of authors is available in Wikipedia.
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