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Information about Carnitine

Carnitine, also known as L-carnitine (levocarnitine) is a quaternary ammonium compound synthesized from the amino acids lysine and methionine primarily in the liver and kidneys.[1] It helps in the consumption and disposal of fat in the body because it is responsible for the transport of fatty acids from the cytosol into the mitochondria. It is often sold as a nutritional supplement. Originally found as a growth factor for mealworms and labeled vitamin Bt.

Natural carnitine is the L-stereoisomer.

Production

It can be synthesised within the body from the amino acids lysine or methionine. Vitamin C (ascorbic acid) is essential to the synthesis of carnitine. It has been speculated that during growth or pregnancy the requirement of carnitine could exceed its natural production.

Role in fatty acid metabolism

Carnitine transports long-chain acyl groups from fatty acids into the mitochondrial matrix, so that they can be broken down through beta-oxidation to acetate to obtain usable energy via the citric acid cycle, or in some organisms such as fungi, to use actetate in the glyoxylate cycle to enter gluconeogenesis for the formation of carbohydrates. Fatty acids must be activated before binding to the carnitine molecule to form acyl-carnitine. The free fatty acid in the cytosol is attached with a thioester bond to coenzyme A (CoA). This reaction is catalyzed by the enzyme fatty acyl-CoA synthetase and driven to completion by inorganic pyrophosphatase.

The acyl group on CoA can now be transferred to carnitine and the resulting acyl-carnitine transported into the mitochondrial matrix. This occurs via a series of similar steps:
  1. Acyl-CoA is conjugated to carnitine by carnitine acyltransferase I (palmitoyltransferase) located on the outer mitochondrial membrane
  2. Acyl-carnitine is shuttled inside by a carnitine-acylcarnitine translocase
  3. Acyl-carnitine is converted to acyl-CoA by carnitine acyltransferase II (palmitoyltransferase) located on the inner mitochondrial membrane. The liberated carnitine returns to the cytosol.


Dysfunction of this process leads to the genetic disorders primary carnitine deficiency, carnitine palmitoyltransferase I deficiency, carnitine palmitoyltransferase II deficiency, and carnitine-acylcarnitine translocase deficiency.

It is important to note that carnitine acyltransferase I undergoes allosteric inhibition as a result of malonyl-CoA, an intermediate in fatty acid biosynthesis, in order to prevent futile cycling between beta-oxidation and fatty acid synthesis.




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Natural sources

The highest concentrations of carnitine are found in red meat and dairy products. Other natural sources of carnitine include nuts and seeds (e.g. pumpkin, sunflower, sesame), legumes or pulses (beans, peas, lentils, peanuts), vegetables (artichokes, asparagus, beet greens, broccoli, brussels sprouts, collard greens, garlic, mustard greens, okra, parsley), fruits (apricots, bananas), cereals (buckwheat, corn, millet, oatmeal, rice bran, rye, whole wheat, wheat bran, wheat germ) and other 'health' foods (bee pollen, brewer's yeast, carob, and kale).

ProductQuantityCarnitine
Beef Steak3.5 oz95 mg
Ground Beef3.5 oz94 mg
Pork3.5 oz27.7 mg
Bacon3.5 oz23.3 mg
Cod Fish3.5 oz 5.6 mg
Chicken Breast3.5 oz 3.9 mg
American Cheese3.5 oz 3.7 mg
Ice Cream3.5 fl oz 3.7 mg
Whole Milk3.5 fl oz 3.3 mg
Cottage Cheese3.5 fl oz 1.1 mg
Whole Wheat Bread3.5 oz 0.36 mg
Asparagus3.5 oz 0.195 mg
White Bread3.5 oz 0.147 mg
Macaroni3.5 oz 0.126 mg
Peanut Butter3.5 oz 0.083 mg
Rice (cooked)3.5 oz 0.0449 mg
Eggs3.5 oz 0.0121 mg
Orange Juice3.5 fl oz 0.0019 mg

Effects on diabetes

L-Carnitine improved glucose disposal among 15 patients with Type II Diabetes and 20 healthy volunteers.[2] Glucose storage increased between both groups, but glucose oxidation increased only in the diabetic group. Finally, glucose uptake increased about 8% for both.

Health supplements

  • Products containing L-carnitine cannot be marketed as "natural health products" in Canada, since L-carnitine is not considered a natural ingredient. L-carnitine products and supplements are not allowed to be imported into the country (Health Canada).[3]

See also

References

  • Olpin S (2005). "Fatty acid oxidation defects as a cause of neuromyopathic disease in infants and adults". Clin. Lab. 51 (5-6): 289-306. PMID 15991803. 
  • Steiber A, Kerner J, Hoppel C (2004). "Carnitine: a nutritional, biosynthetic, and functional perspective". Mol. Aspects Med. 25 (5-6): 455-73. PMID 15363636. 

Footnotes

1. ^ L-Carnitine. Retrieved on 2007-06-01.
2. ^ Geltrude Mingrone, Aldo V. Greco, Esmeralda Capristo, Giuseppe Benedetti, Annalisa Giancaterini, Andrea De Gaetano, and Giovanni Gasbarrini (1999). "L-Carnitine Improves Glucose Disposal in Type 2 Diabetic Patients". Journal of the American College of Nutrition 18 (1): 77-82. 
3. ^ NHPD Monthly Communique, Vol. 1, Issue 1, September 2005. Retrieved on 2007-06-01.

External links

 •  • [ e]
Dietary supplements
TypesAmino acids • Bodybuilding supplement • Energy drink • Energy bar • Fatty acids • Herbal Supplements • Minerals • Probiotics • Vitamins • Whole food supplements
Vitamins and mineralsRetinol (Vitamin A) • B vitamins: Thiamine (B1) • Riboflavin (B2)• Niacin (B3)• Pantothenic acid (B5)• Pyridoxine (B6)• Biotin (B7)• Folic acid (B9) • Cyanocobalamin (B12) • Ascorbic acid (Vitamin C) • Ergocalciferol and Cholecalciferol (Vitamin D) • Tocopherol (Vitamin E) • Naphthoquinone (Vitamin K) • Calcium • Choline • Chlorine • Chromium • Cobalt • Copper • Fluorine • Iodine • Iron • Magnesium • Manganese • Molybdenum • Phosphorus • Potassium • Selenium • Sodium • Sulfur • Zinc
Other common ingredientsCarnitine • Chondroitin sulfate • Cod liver oil • Copper gluconate • Creatine • Dietary fiber • Elemental calcium • Ephedra • Fish oil • Folic acid • Ginseng • Glucosamine • Glutamine • Iron supplements • Japanese Honeysuckle • Krill oil • Lactobacillus • Lingzhi • Linseed oil • Red yeast rice • Royal jelly • Saw palmetto • Spirulina • Taurine • Wheatgrass • Wolfberry • Yohimbine • Zinc gluconate
Related articlesCodex Alimentarius • Enzyte • Metabolife • Hadacol • Nutraceutical • Multivitamin
 •  • [ e]
Other alimentary tract and metabolism products (A16)
Amino acids and derivativesLevocarnitine - Ademetionine - Levoglutamide - Mercaptamine - Carglumic acid - Betaine
EnzymesAlglucerase - Imiglucerase - Agalsidase alfa - Agalsidase beta - Laronidase - Sacrosidase - Alglucosidase alfa - Galsulfase - Idursulfase
Various alimentary tract
and metabolism products		Tioctic acid - Anethole trithione - Sodium phenylbutyrate - Nitisinone - Zinc acetate - Miglustat
Quaternary ammonium cations, also known as quats, are positively charged polyatomic ions of the structure NR4+ with R being alkyl groups. Unlike the ammonium ion NH4+
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amino acid is a molecule that contains both amine and carboxyl functional groups. In biochemistry, this term refers to alpha-amino acids with the general formula H2NCHRCOOH, where R is an organic substituent.
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Lysine (abbreviated as Lys or K)[1] is an α-amino acid with the chemical formula HO2CCH(NH2)(CH2)4NH2.
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Methionine (abbreviated as Met or M)[1] is an α-amino acid with the chemical formula HO2CCH(NH2)CH2CH2SCH3. This essential amino acid is classified as nonpolar.
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liver is an organ present in vertebrates and some other animals. It plays a major role in metabolism and has a number of functions in the body, including glycogen storage, decomposition of red blood cells, plasma protein synthesis, and detoxification.
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The kidneys are organs that filter wastes (such as urea) from the blood and excrete them, along with water, as urine. The medical field that studies the kidneys and diseases of the kidney is called nephrology[1].
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Types of Fats in Food
  • Unsaturated fat
  • Monounsaturated fat
  • Polyunsaturated fat
  • Trans fat
  • Omega: 3, 6, 9

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The cytosol (cf. cytoplasm, which also includes the organelles) is the internal fluid of the cell, and a portion of cell metabolism occurs here. Proteins within the cytosol play an important role in signal transduction pathways and glycolysis.
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dietary supplement (also known as food supplement) is intended to supply nutrients, (vitamins, minerals, fatty acids or amino acids) that are missing or not consumed in sufficient quantity in a person's diet.
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The term growth factor refers to a naturally occurring protein capable of stimulating cellular proliferation and cellular differentiation. Growth factors are important for regulating a variety of cellular processes.
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T. molitor

Binomial name
Tenebrio molitor
Linnaeus, 1758

Mealworms are the larval form of the mealworm beetle, Tenebrio molitor, a species of darkling beetle.
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A vitamin is a nutrient that is an organic compound required in tiny amounts for essential metabolic reactions in a living organism.[1] The term vitamin
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Stereoisomers are isomeric molecules whose atomic connectivity is the same but whose atomic arrangement in space is different.

Enantiomers

Main article: enantiomer

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Lysine (abbreviated as Lys or K)[1] is an α-amino acid with the chemical formula HO2CCH(NH2)(CH2)4NH2.
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Methionine (abbreviated as Met or M)[1] is an α-amino acid with the chemical formula HO2CCH(NH2)CH2CH2SCH3. This essential amino acid is classified as nonpolar.
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Vitamin C or L -ascorbate is an essential nutrient for higher primates, and a small number of other species. The presence of ascorbate is required for a range of essential metabolic reactions in all animals and in plants and is made internally by almost all organisms,
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Ascorbic acid is an organic acid with antioxidant properties. Its appearance is white to light yellow crystals or powder. It is water soluble. The L-enantiomer of ascorbic acid is commonly known as vitamin C.
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prepubescence) (4-10)
  • Elementary school age (also called middle childhood) (4-9)
  • Preadolescence (preteen, or late childhood.
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    • Pregnancy is the carrying of one or more offspring, known as a fetus or embryo, inside the body of a female mammal such as a human. In a pregnancy, there can be multiple gestations (for example, in the case of twins or triplets).
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    matrix contains soluble enzymes that catalyze the oxidation of pyruvate and other small organic molecules.

    The mitochondrial matrix also contains the mitochondria's DNA and ribosomes.
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    Beta oxidation is the process by which fatty acids, in the form of Acyl-CoA molecules, are broken down in the mitochondria and/or in peroxisomes to generate Acetyl-CoA, the entry molecule for the Krebs Cycle.

    Occurs in mitochondrial matrix.
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    An acetate, or ethanoate, is a salt or ester of acetic acid.

    Acetate anion

    The acetate anion, [C2H3O2]−, is a carboxylate and is the conjugate base of acetic acid.
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    citric acid cycle, also known as the tricarboxylic acid (TCA) cycle, the Krebs cycle, or Szent-Györgyi-Krebs cycle (after Hans Adolf Krebs and Albert Szent-Györgyi who first determined the chemical intermediates and reaction sequence of the cycle), is a series
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    The glyoxylate cycle is a metabolic pathway occurring in plants, certain vertebrates, and several microorganisms, such as E. coli and yeast.

    The glyoxylate cycle allows these organisms to use fats for the synthesis of carbohydrates, a task which most vertebrates, including
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    Gluconeogenesis is the generation of glucose from non-sugar carbon substrates like pyruvate, lactate, glycerol, and glucogenic amino acids (primarily alanine and glutamine).
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    Coenzyme A (CoA, CoASH, or HSCoA) is a coenzyme, notable for its role in the synthesis and oxidization of fatty acids, and the oxidation of pyruvate in the citric acid cycle. It is adapted from cysteamine, pantothenate, and adenosine triphosphate.
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    ACSL6 is a gene which codes an enzyme involved in fatty acid degradation.

    External links

    • MeSH ACSL6+protein,+human


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    Pyrophosphatase are acid anhydride hydrolases that act upon diphosphate bonds.

    Examples include:
    • Inorganic pyrophosphatase
    • Thiamine pyrophosphatase

    External links

    • MeSH Pyrophosphatases

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