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Record Information
Version2.0
Creation Date2009-07-21 20:27:12 UTC
Update Date2014-12-24 20:25:52 UTC
Accession NumberT3D2832
Identification
Common NameL-Carnitine
ClassSmall Molecule
DescriptionCarnitine is not an essential amino acid; it can be synthesized in the body. However, it is so important in providing energy to muscles including the heart-that some researchers are now recommending carnitine supplements in the diet, particularly for people who do not consume much red meat, the main food source for carnitine. Carnitine has been described as a vitamin, an amino acid, or a metabimin, i.e., an essential metabolite. Like the B vitamins, carnitine contains nitrogen and is very soluble in water, and to some researchers carnitine is a vitamin (Liebovitz 1984). It was found that an animal (yellow mealworm) could not grow without carnitine in its diet. However, as it turned out, almost all other animals, including humans, do make their own carnitine; thus, it is no longer considered a vitamin. Nevertheless, in certain circumstances-such as deficiencies of methionine, lysine or vitamin C or kidney dialysis--carnitine shortages develop. Under these conditions, carnitine must be absorbed from food, and for this reason it is sometimes referred to as a metabimin or a conditionally essential metabolite. Like the other amino acids used or manufactured by the body, carnitine is an amine. But like choline, which is sometimes considered to be a B vitamin, carnitine is also an alcohol (specifically, a trimethylated carboxy-alcohol). Thus, carnitine is an unusual amino acid and has different functions than most other amino acids, which are most usually employed by the body in the construction of protein. Carnitine is an essential factor in fatty acid metabolism in mammals. It's most important known metabolic function is to transport fat into the mitochondria of muscle cells, including those in the heart, for oxidation. This is how the heart gets most of its energy. In humans, about 25% of carnitine is synthesized in the liver, kidney and brain from the amino acids lysine and methionine. Most of the carnitine in the body comes from dietary sources such as red meat and dairy products. Inborn errors of carnitine metabolism can lead to brain deterioration like that of Reye's syndrome, gradually worsening muscle weakness, Duchenne-like muscular dystrophy and extreme muscle weakness with fat accumulation in muscles. Borurn et al. (1979) describe carnitine as an essential nutrient for pre-term babies, certain types (non-ketotic) of hypoglycemics, kidney dialysis patients, cirrhosis, and in kwashiorkor, type IV hyperlipidemia, heart muscle disease (cardiomyopathy), and propionic or organic aciduria (acid urine resulting from genetic or other anomalies). In all these conditions and the inborn errors of carnitine metabolism, carnitine is essential to life and carnitine supplements are valuable. carnitine therapy may also be useful in a wide variety of clinical conditions. carnitine supplementation has improved some patients who have angina secondary to coronary artery disease. It may be worth a trial in any form of hyperlipidemia or muscle weakness. carnitine supplements may be useful in many forms of toxic or metabolic liver disease and in cases of heart muscle disease. Hearts undergoing severe arrhythmia quickly deplete their stores of carnitine. Athletes, particularly in Europe, have used carnitine supplements for improved endurance. carnitine may improve muscle building by improving fat utilization and may even be useful in treating obesity. carnitine joins a long list of nutrients which may be of value in treating pregnant women, hypothyroid individuals, and male infertility due to low motility of sperm. Even the Physician's Desk Reference gives indication for carnitine supplements as improving the tolerance of ischemic heart disease, myocardial insufficiencies, and type IV hyperlipoproteinemia. carnitine deficiency is noted in abnormal liver function, renal dialysis patients, and severe to moderate muscular weakness with associated anorexia.
Compound Type
  • Dietary Supplement
  • Drug
  • Food Toxin
  • Metabolite
  • Natural Compound
  • Nootropic Agent
  • Nutraceutical
  • Organic Compound
  • Vitamin B Complex
Chemical Structure
Thumb
Synonyms
Synonym
(-)-(R)-3-Hydroxy-4-(trimethylammonio)butyrate
(-)-carnitine
(-)-L-Carnitin
(-)-L-Carnitine
(R)-(3-Carboxy-2-hydroxypropyl)trimethylammonium hydroxide
(R)-carnitine
(S)-carnitine
1-Carnitine
3-Carboxy-2-hydroxy-N,N,N-trimethyl-1-propanaminium
3-Carboxy-2-hydroxy-N,N,N-trimethyl-1-propanaminium hydroxide, inner salt
3-Hydroxy-4-trimethylammoniobutanoate
3-Hydroxy-4-trimethylammoniobutanoic acid
Albicar
Aveptol
Bicarnesine
Biocarn
Bitobionil
Cardimax
Cardispan
Carniben
Carnicor
Carniking
Carniking 50
Carnilean
Carnipass
Carnipass 20
Carnitene
Carnitine
Carnitor
D-Carnitine
delta-Carnitine
DL-carnitine
gamma-Trimethyl-ammonium-beta-hydroxybutirate
gamma-Trimethyl-beta-hydroxybutyrobetaine
gamma-Trimethyl-hydroxybutyrobetaine
Karnitin
L-(-)-Carnitine
L-gamma-Trimethyl-beta-hydroxybutyrobetaine
Lecarna
Levocarnitin
Levocarnitina
Levocarnitine
Levocarnitinum
R-(-)-3-Hydroxy-4-trimethylaminobutyrate
Vitamin BT
Chemical FormulaC7H15NO3
Average Molecular Mass161.199 g/mol
Monoisotopic Mass161.105 g/mol
CAS Registry Number541-15-1
IUPAC Name(3R)-3-hydroxy-4-(trimethylazaniumyl)butanoate
Traditional NameL-carnitine
SMILES[H][C@@](O)(CC([O-])=O)C[N+](C)(C)C
InChI IdentifierInChI=1S/C7H15NO3/c1-8(2,3)5-6(9)4-7(10)11/h6,9H,4-5H2,1-3H3/t6-/m1/s1
InChI KeyInChIKey=PHIQHXFUZVPYII-ZCFIWIBFSA-N
Chemical Taxonomy
Description belongs to the class of organic compounds known as carnitines. These are organic compounds containing the quaternary ammonium compound carnitine.
KingdomOrganic compounds
Super ClassOrganic nitrogen compounds
ClassOrganonitrogen compounds
Sub ClassQuaternary ammonium salts
Direct ParentCarnitines
Alternative Parents
Substituents
  • Carnitine
  • Beta-hydroxy acid
  • Short-chain hydroxy acid
  • Fatty acid
  • Hydroxy acid
  • Tetraalkylammonium salt
  • 1,2-aminoalcohol
  • Carboxylic acid salt
  • Secondary alcohol
  • Carboxylic acid derivative
  • Carboxylic acid
  • Monocarboxylic acid or derivatives
  • Organic oxygen compound
  • Organooxygen compound
  • Organic zwitterion
  • Organic salt
  • Hydrocarbon derivative
  • Organic oxide
  • Carbonyl group
  • Organopnictogen compound
  • Amine
  • Alcohol
  • Aliphatic acyclic compound
Molecular FrameworkAliphatic acyclic compounds
External Descriptors
Biological Properties
StatusDetected and Not Quantified
OriginEndogenous
Cellular Locations
  • Cytoplasm
  • Endoplasmic reticulum
  • Extracellular
  • Membrane
  • Mitochondria
  • Peroxisome
Biofluid LocationsNot Available
Tissue Locations
  • Adipose Tissue
  • Bladder
  • Brain
  • Erythrocyte
  • Fibroblasts
  • Intestine
  • Kidney
  • Liver
  • Lung
  • Muscle
  • Myocardium
  • Nerve Cells
  • Neuron
  • Platelet
  • Prostate
  • Skeletal Muscle
  • Sperm
  • Testes
Pathways
NameSMPDB LinkKEGG Link
Beta Oxidation of Very Long Chain Fatty AcidsSMP00052 map01040
Carnitine SynthesisSMP00465 Not Available
Mitochondrial Beta-Oxidation of Long Chain Saturated Fatty AcidsSMP00482 Not Available
Mitochondrial Beta-Oxidation of Short Chain Saturated Fatty AcidsSMP00480 Not Available
Oxidation of Branched Chain Fatty AcidsSMP00030 Not Available
Carnitine palmitoyl transferase deficiency (I)SMP00538 Not Available
Lysinuric Protein IntoleranceSMP00197 Not Available
Propionic AcidemiaSMP00236 Not Available
Applications
Biological Roles
Chemical RolesNot Available
Physical Properties
StateSolid
AppearanceWhite powder.
Experimental Properties
PropertyValue
Melting Point195-198°C
Boiling PointNot Available
Solubility2500 mg/mL
LogPNot Available
Predicted Properties
PropertyValueSource
Water Solubility5.33 g/LALOGPS
logP-2.9ALOGPS
logP-4.9ChemAxon
logS-1.6ALOGPS
pKa (Strongest Acidic)4.2ChemAxon
pKa (Strongest Basic)-3.6ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count3ChemAxon
Hydrogen Donor Count1ChemAxon
Polar Surface Area60.36 ŲChemAxon
Rotatable Bond Count4ChemAxon
Refractivity63.49 m³·mol⁻¹ChemAxon
Polarizability16.93 ųChemAxon
Number of Rings0ChemAxon
Bioavailability1ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Spectra
Spectra
Spectrum TypeDescriptionSplash KeyView
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (Non-derivatized) - 70eV, Positivesplash10-00di-9100000000-1b25dacb04c3ed5be8d0JSpectraViewer
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (1 TMS) - 70eV, Positivesplash10-00di-9100000000-c15eaa190d1e28a4839aJSpectraViewer
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (Non-derivatized) - 70eV, PositiveNot AvailableJSpectraViewer
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (TMS_1_1) - 70eV, PositiveNot AvailableJSpectraViewer
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (TMS_1_2) - 70eV, PositiveNot AvailableJSpectraViewer
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (TMS_2_1) - 70eV, PositiveNot AvailableJSpectraViewer
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (TBDMS_1_1) - 70eV, PositiveNot AvailableJSpectraViewer
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (TBDMS_1_2) - 70eV, PositiveNot AvailableJSpectraViewer
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (TBDMS_2_1) - 70eV, PositiveNot AvailableJSpectraViewer
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ , positivesplash10-03di-0900000000-9b579c570aab7c7d3a21JSpectraViewer | MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ , positivesplash10-0ik9-0900000000-e37d3def2de1af5bd2f5JSpectraViewer | MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ , positivesplash10-0ue9-8900000000-cf37f0a721cd52d86e8eJSpectraViewer | MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ , positivesplash10-0r0c-9200000000-a11a4872036f3c33d25aJSpectraViewer | MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ , positivesplash10-0a4l-9000000000-2402e260a330ff1772a1JSpectraViewer | MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-IT , positivesplash10-0w29-6900000000-d0136248acdd706e650bJSpectraViewer | MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QTOF , positivesplash10-0ik9-2900000000-61732bb10307f2b183caJSpectraViewer | MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QTOF , positivesplash10-0zg0-9400000000-15c3db3324f1d46d3c7cJSpectraViewer | MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QTOF , positivesplash10-0ik9-2900000000-ee79f10dce9fc09246ecJSpectraViewer | MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-03di-1900000000-dd1b1a023937cdcb11afJSpectraViewer
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-114i-3900000000-9f24d3bc535736149e2aJSpectraViewer
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-0a4l-9000000000-632ef17d9dde38586990JSpectraViewer
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-01ox-0900000000-3bffd5143cf8b072299eJSpectraViewer
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-00kf-0900000000-e68f553bcb15d3ef5b47JSpectraViewer
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-00di-9200000000-c5b43723951af6da48cfJSpectraViewer
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-03di-3900000000-97af6636a917c0edea61JSpectraViewer
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-01pc-9300000000-543e21cb6b9785149e31JSpectraViewer
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-08fr-9000000000-9128d6fe96d9c7276695JSpectraViewer
1D NMR1H NMR SpectrumNot AvailableJSpectraViewer
Toxicity Profile
Route of ExposureIntravenous, Oral. Absolute bioavailability is 15% (tablets or solution). Time to maximum plasma concentration was found to be 3.3 hours.
Mechanism of ToxicityLevocarnitine can be synthesised within the body from the amino acids lysine or methionine. Vitamin C (ascorbic acid) is essential to the synthesis of carnitine. Levocarnitine is a carrier molecule in the transport of long chain fatty acids across the inner mitochondrial membrane. It also exports acyl groups from subcellular organelles and from cells to urine before they accumulate to toxic concentrations. Only the L isomer of carnitine (sometimes called vitamin BT) affects lipid metabolism. Levocarnitine is handled by several proteins in different pathways including carnitine transporters, carnitine translocases, carnitine acetyltransferases and carnitine palmitoyltransferases.
MetabolismAfter oral administration L-carnitine which is unabsorbed is metabolized in the gastrointestinal tract by bacterial microflora. Major metabolites include trimethylamine N-oxide and [3H]-gamma-butyrobetaine. Route of Elimination: Following a single intravenous dose, 73.1 +/- 16% of the dose was excreted in the urine during the 0-24 hour interval. Post administration of oral carnitine supplements, in addition to a high carnitine diet, 58-65% of the administered radioactive dose was recovered from urine and feces in 5-11 days. Half Life: 17.4 hours (elimination) following a single intravenous dose.
Toxicity ValuesLD50 > 8g/kg (mouse, oral).
Lethal DoseNot Available
Carcinogenicity (IARC Classification)No indication of carcinogenicity to humans (not listed by IARC).
Uses/SourcesFor treatment of primary systemic carnitine deficiency, a genetic impairment of normal biosynthesis or utilization of levocarnitine from dietary sources, or for the treatment of secondary carnitine deficiency resulting from an inborn error of metabolism such as glutaric aciduria II, methyl malonic aciduria, propionic acidemia, and medium chain fatty acylCoA dehydrogenase deficiency. Used therapeutically to stimulate gastric and pancreatic secretions and in the treatment of hyperlipoproteinemias. Parenteral levocarnitine is indicated for the prevention and treatment of carnitine deficiency in patients with end-stage renal disease.
Minimum Risk LevelNot Available
Health EffectsNot Available
SymptomsAdverse effects include hypertension, fever, tachycardia and seizures.
TreatmentNot Available
Normal Concentrations
Not Available
Abnormal Concentrations
Not Available
DrugBank IDDB00583
HMDB IDHMDB00062
PubChem Compound ID10917
ChEMBL IDCHEMBL1149
ChemSpider ID10455
KEGG IDC00318
UniProt IDNot Available
OMIM ID201450 , 212138 , 212140 , 212160 , 236795 , 255120
ChEBI ID16347
BioCyc IDCARNITINE
CTD IDNot Available
Stitch IDL-Carnitine
PDB ID152
ACToR IDNot Available
Wikipedia LinkL-Carnitine
References
Synthesis Reference

Noguchi, J. and Sakota, N.; US. Patent 3,135,788; June 2,1964; assigned to Nihon Zoki Seiyaku Kabushikikaisha (Japan).

MSDSLink
General References
  1. Olpin SE: Fatty acid oxidation defects as a cause of neuromyopathic disease in infants and adults. Clin Lab. 2005;51(5-6):289-306. [15991803 ]
  2. Steiber A, Kerner J, Hoppel CL: Carnitine: a nutritional, biosynthetic, and functional perspective. Mol Aspects Med. 2004 Oct-Dec;25(5-6):455-73. [15363636 ]
  3. Wachter S, Vogt M, Kreis R, Boesch C, Bigler P, Hoppeler H, Krahenbuhl S: Long-term administration of L-carnitine to humans: effect on skeletal muscle carnitine content and physical performance. Clin Chim Acta. 2002 Apr;318(1-2):51-61. [11880112 ]
  4. Evans AM, Fornasini G: Pharmacokinetics of L-carnitine. Clin Pharmacokinet. 2003;42(11):941-67. [12908852 ]
  5. Pastoris O, Dossena M, Foppa P, Catapano M, Arbustini E, Bellini O, Dal Bello B, Minzioni G, Ceriana P, Barzaghi N: Effect of L-carnitine on myocardial metabolism: results of a balanced, placebo-controlled, double-blind study in patients undergoing open heart surgery. Pharmacol Res. 1998 Feb;37(2):115-22. [9572066 ]
  6. Stephens FB, Constantin-Teodosiu D, Laithwaite D, Simpson EJ, Greenhaff PL: Insulin stimulates L-carnitine accumulation in human skeletal muscle. FASEB J. 2006 Feb;20(2):377-9. Epub 2005 Dec 20. [16368715 ]
  7. Tamai I, China K, Sai Y, Kobayashi D, Nezu J, Kawahara E, Tsuji A: Na(+)-coupled transport of L-carnitine via high-affinity carnitine transporter OCTN2 and its subcellular localization in kidney. Biochim Biophys Acta. 2001 Jun 6;1512(2):273-84. [11406104 ]
  8. Malaguarnera M, Pistone G, Astuto M, Dell'Arte S, Finocchiaro G, Lo Giudice E, Pennisi G: L-Carnitine in the treatment of mild or moderate hepatic encephalopathy. Dig Dis. 2003;21(3):271-5. [14571103 ]
  9. Oey NA, van Vlies N, Wijburg FA, Wanders RJ, Attie-Bitach T, Vaz FM: L-carnitine is synthesized in the human fetal-placental unit: potential roles in placental and fetal metabolism. Placenta. 2006 Aug;27(8):841-6. Epub 2005 Nov 18. [16300828 ]
  10. Feinfeld DA, Kurian P, Cheng JT, Dilimetin G, Arriola MR, Ward L, Manis T, Carvounis CP: Effect of oral L-carnitine on serum myoglobin in hemodialysis patients. Ren Fail. 1996 Jan;18(1):91-6. [8820505 ]
  11. Matalliotakis I, Koumantaki Y, Evageliou A, Matalliotakis G, Goumenou A, Koumantakis E: L-carnitine levels in the seminal plasma of fertile and infertile men: correlation with sperm quality. Int J Fertil Womens Med. 2000 May-Jun;45(3):236-40. [10929687 ]
  12. Vescovo G, Ravara B, Gobbo V, Dalla Libera L: Inflammation and perturbation of the l-carnitine system in heart failure. Eur J Heart Fail. 2005 Oct;7(6):997-1002. [16227137 ]
  13. Lerch R: [The effect of L-carnitine on ischemic heart disease: experimental results]. Praxis (Bern 1994). 1998 Jan 21;87(4):97-100. [9522638 ]
  14. Khademi A, Alleyassin A, Safdarian L, Hamed EA, Rabiee E, Haghaninezhad H: The effects of L-carnitine on sperm parameters in smoker and non-smoker patients with idiopathic sperm abnormalities. J Assist Reprod Genet. 2005 Dec;22(11-12):395-9. [16331536 ]
  15. Stradomska TJ, Tylki-Szymanska A, Bentkowski Z: Very long-chain fatty acids in Rett syndrome. Eur J Pediatr. 1999 Mar;158(3):226-9. [10094444 ]
  16. Hoppel CL, Genuth SM: Urinary excretion of acetylcarnitine during human diabetic and fasting ketosis. Am J Physiol. 1982 Aug;243(2):E168-72. [6810706 ]
  17. Waldner R, Laschan C, Lohninger A, Gessner M, Tuchler H, Huemer M, Spiegel W, Karlic H: Effects of doxorubicin-containing chemotherapy and a combination with L-carnitine on oxidative metabolism in patients with non-Hodgkin lymphoma. J Cancer Res Clin Oncol. 2006 Feb;132(2):121-8. Epub 2005 Nov 8. [16283381 ]
  18. Lenzi A, Sgro P, Salacone P, Paoli D, Gilio B, Lombardo F, Santulli M, Agarwal A, Gandini L: A placebo-controlled double-blind randomized trial of the use of combined l-carnitine and l-acetyl-carnitine treatment in men with asthenozoospermia. Fertil Steril. 2004 Jun;81(6):1578-84. [15193480 ]
  19. Sinclair C, Gilchrist JM, Hennessey JV, Kandula M: Muscle carnitine in hypo- and hyperthyroidism. Muscle Nerve. 2005 Sep;32(3):357-9. [15803480 ]
  20. Ahmad S: L-carnitine in dialysis patients. Semin Dial. 2001 May-Jun;14(3):209-17. [11422928 ]
  21. Shihabi ZK, Oles KS, McCormick CP, Penry JK: Serum and tissue carnitine assay based on dialysis. Clin Chem. 1992 Aug;38(8 Pt 1):1414-7. [1643708 ]
  22. Sreekumar A, Poisson LM, Rajendiran TM, Khan AP, Cao Q, Yu J, Laxman B, Mehra R, Lonigro RJ, Li Y, Nyati MK, Ahsan A, Kalyana-Sundaram S, Han B, Cao X, Byun J, Omenn GS, Ghosh D, Pennathur S, Alexander DC, Berger A, Shuster JR, Wei JT, Varambally S, Beecher C, Chinnaiyan AM: Metabolomic profiles delineate potential role for sarcosine in prostate cancer progression. Nature. 2009 Feb 12;457(7231):910-4. doi: 10.1038/nature07762. [19212411 ]
Gene Regulation
Up-Regulated GenesNot Available
Down-Regulated GenesNot Available

Targets

General Function:
Symporter activity
Specific Function:
Sodium-ion dependent, high affinity carnitine transporter. Involved in the active cellular uptake of carnitine. Transports one sodium ion with one molecule of carnitine. Also transports organic cations such as tetraethylammonium (TEA) without the involvement of sodium. Also relative uptake activity ratio of carnitine to TEA is 11.3.
Gene Name:
SLC22A5
Uniprot ID:
O76082
Molecular Weight:
62751.08 Da
References
  1. Lahjouji K, Elimrani I, Wu J, Mitchell GA, Qureshi IA: A heterozygote phenotype is present in the jvs +/- mutant mouse livers. Mol Genet Metab. 2002 May;76(1):76-80. [12175785 ]
  2. Kristufek D, Rudorfer W, Pifl C, Huck S: Organic cation transporter mRNA and function in the rat superior cervical ganglion. J Physiol. 2002 Aug 15;543(Pt 1):117-34. [12181285 ]
  3. Ohashi R, Tamai I, Inano A, Katsura M, Sai Y, Nezu J, Tsuji A: Studies on functional sites of organic cation/carnitine transporter OCTN2 (SLC22A5) using a Ser467Cys mutant protein. J Pharmacol Exp Ther. 2002 Sep;302(3):1286-94. [12183691 ]
  4. Hou JW: Primary systemic carnitine deficiency presenting as recurrent Reye-like syndrome and dilated cardiomyopathy. Chang Gung Med J. 2002 Dec;25(12):832-7. [12635840 ]
  5. Friedrich A, Prasad PD, Freyer D, Ganapathy V, Brust P: Molecular cloning and functional characterization of the OCTN2 transporter at the RBE4 cells, an in vitro model of the blood-brain barrier. Brain Res. 2003 Apr 4;968(1):69-79. [12644265 ]
  6. Todesco L, Bodmer M, Vonwil K, Haussinger D, Krahenbuhl S: Interaction between pivaloylcarnitine and L-carnitine transport into L6 cells overexpressing hOCTN2. Chem Biol Interact. 2009 Aug 14;180(3):472-7. doi: 10.1016/j.cbi.2009.02.014. Epub 2009 Mar 11. [19539806 ]
General Function:
Receptor binding
Specific Function:
Carnitine acetylase is specific for short chain fatty acids. Carnitine acetylase seems to affect the flux through the pyruvate dehydrogenase complex. It may be involved as well in the transport of acetyl-CoA into mitochondria.
Gene Name:
CRAT
Uniprot ID:
P43155
Molecular Weight:
70857.055 Da
References
  1. Jogl G, Tong L: Crystal structure of carnitine acetyltransferase and implications for the catalytic mechanism and fatty acid transport. Cell. 2003 Jan 10;112(1):113-22. [12526798 ]
  2. Wu D, Govindasamy L, Lian W, Gu Y, Kukar T, Agbandje-McKenna M, McKenna R: Structure of human carnitine acetyltransferase. Molecular basis for fatty acyl transfer. J Biol Chem. 2003 Apr 11;278(15):13159-65. Epub 2003 Jan 31. [12562770 ]
  3. Vikramadithyan RK, Hiriyan J, Suresh J, Gershome C, Babu RK, Misra P, Rajagopalan R, Chakrabarti R: DRF 2655: a unique molecule that reduces body weight and ameliorates metabolic abnormalities. Obes Res. 2003 Feb;11(2):292-303. [12582227 ]
  4. Govindasamy L, Kukar T, Lian W, Pedersen B, Gu Y, Agbandje-McKenna M, Jin S, McKenna R, Wu D: Structural and mutational characterization of L-carnitine binding to human carnitine acetyltransferase. J Struct Biol. 2004 Jun;146(3):416-24. [15099582 ]
  5. Cordente AG, Lopez-Vinas E, Vazquez MI, Swiegers JH, Pretorius IS, Gomez-Puertas P, Hegardt FG, Asins G, Serra D: Redesign of carnitine acetyltransferase specificity by protein engineering. J Biol Chem. 2004 Aug 6;279(32):33899-908. Epub 2004 May 21. [15155769 ]
General Function:
Carnitine o-palmitoyltransferase activity
Specific Function:
Catalyzes the transfer of the acyl group of long-chain fatty acid-CoA conjugates onto carnitine, an essential step for the mitochondrial uptake of long-chain fatty acids and their subsequent beta-oxidation in the mitochondrion. Plays an important role in triglyceride metabolism.
Gene Name:
CPT1A
Uniprot ID:
P50416
Molecular Weight:
88366.92 Da
References
  1. Xu ZR, Wang MQ, Mao HX, Zhan XA, Hu CH: Effects of L-carnitine on growth performance, carcass composition, and metabolism of lipids in male broilers. Poult Sci. 2003 Mar;82(3):408-13. [12705401 ]
  2. Morillas M, Lopez-Vinas E, Valencia A, Serra D, Gomez-Puertas P, Hegardt FG, Asins G: Structural model of carnitine palmitoyltransferase I based on the carnitine acetyltransferase crystal. Biochem J. 2004 May 1;379(Pt 3):777-84. [14711372 ]
  3. Tripodi G, Modica R, Stella A, Bigatti G, Bianchi G, Stella P: Haplotype analysis of carnitine transporters and left ventricular mass in human essential hypertension. J Ren Nutr. 2005 Jan;15(1):2-7. [15647998 ]
  4. Waldner R, Laschan C, Lohninger A, Gessner M, Tuchler H, Huemer M, Spiegel W, Karlic H: Effects of doxorubicin-containing chemotherapy and a combination with L-carnitine on oxidative metabolism in patients with non-Hodgkin lymphoma. J Cancer Res Clin Oncol. 2006 Feb;132(2):121-8. Epub 2005 Nov 8. [16283381 ]
  5. Shin ES, Cho SY, Lee EH, Lee SJ, Chang IS, Lee TR: Positive regulation of hepatic carnitine palmitoyl transferase 1A (CPT1A) activities by soy isoflavones and L-carnitine. Eur J Nutr. 2006 Mar;45(3):159-64. Epub 2005 Dec 20. [16362726 ]
General Function:
Carnitine o-palmitoyltransferase activity
Specific Function:
Not Available
Gene Name:
CPT2
Uniprot ID:
P23786
Molecular Weight:
73776.335 Da
References
  1. Barrero MJ, Camarero N, Marrero PF, Haro D: Control of human carnitine palmitoyltransferase II gene transcription by peroxisome proliferator-activated receptor through a partially conserved peroxisome proliferator-responsive element. Biochem J. 2003 Feb 1;369(Pt 3):721-9. [12408750 ]
  2. Kong JY, Rabkin SW: Lovastatin does not accentuate but is rather additive to palmitate-induced apoptosis in cardiomyocytes. Prostaglandins Leukot Essent Fatty Acids. 2002 Nov;67(5):293-302. [12445488 ]
  3. Rasmussen BB, Holmback UC, Volpi E, Morio-Liondore B, Paddon-Jones D, Wolfe RR: Malonyl coenzyme A and the regulation of functional carnitine palmitoyltransferase-1 activity and fat oxidation in human skeletal muscle. J Clin Invest. 2002 Dec;110(11):1687-93. [12464674 ]
  4. Price NT, Jackson VN, van der Leij FR, Cameron JM, Travers MT, Bartelds B, Huijkman NC, Zammit VA: Cloning and expression of the liver and muscle isoforms of ovine carnitine palmitoyltransferase 1: residues within the N-terminus of the muscle isoform influence the kinetic properties of the enzyme. Biochem J. 2003 Jun 15;372(Pt 3):871-9. [12662154 ]
  5. Lehtihet M, Welsh N, Berggren PO, Cook GA, Sjoholm A: Glibenclamide inhibits islet carnitine palmitoyltransferase 1 activity, leading to PKC-dependent insulin exocytosis. Am J Physiol Endocrinol Metab. 2003 Aug;285(2):E438-46. Epub 2003 Apr 8. [12684219 ]
General Function:
Symporter activity
Specific Function:
Sodium-ion dependent, low affinity carnitine transporter. Probably transports one sodium ion with one molecule of carnitine. Also transports organic cations such as tetraethylammonium (TEA) without the involvement of sodium. Relative uptake activity ratio of carnitine to TEA is 1.78. A key substrate of this transporter seems to be ergothioneine (ET).
Gene Name:
SLC22A4
Uniprot ID:
Q9H015
Molecular Weight:
62154.48 Da
References
  1. Kristufek D, Rudorfer W, Pifl C, Huck S: Organic cation transporter mRNA and function in the rat superior cervical ganglion. J Physiol. 2002 Aug 15;543(Pt 1):117-34. [12181285 ]
  2. Amat di San Filippo C, Wang Y, Longo N: Functional domains in the carnitine transporter OCTN2, defective in primary carnitine deficiency. J Biol Chem. 2003 Nov 28;278(48):47776-84. Epub 2003 Sep 23. [14506273 ]
  3. Lamhonwah AM, Ackerley C, Onizuka R, Tilups A, Lamhonwah D, Chung C, Tao KS, Tellier R, Tein I: Epitope shared by functional variant of organic cation/carnitine transporter, OCTN1, Campylobacter jejuni and Mycobacterium paratuberculosis may underlie susceptibility to Crohn's disease at 5q31. Biochem Biophys Res Commun. 2005 Dec 2;337(4):1165-75. Epub 2005 Oct 6. [16246312 ]
  4. Lash LH, Putt DA, Cai H: Membrane transport function in primary cultures of human proximal tubular cells. Toxicology. 2006 Dec 7;228(2-3):200-18. Epub 2006 Sep 1. [16997449 ]
General Function:
Not Available
Specific Function:
Mediates the transport of acylcarnitines of different length across the mitochondrial inner membrane from the cytosol to the mitochondrial matrix for their oxidation by the mitochondrial fatty acid-oxidation pathway.
Gene Name:
SLC25A20
Uniprot ID:
O43772
Molecular Weight:
32943.46 Da
References
  1. Sekoguchi E, Sato N, Yasui A, Fukada S, Nimura Y, Aburatani H, Ikeda K, Matsuura A: A novel mitochondrial carnitine-acylcarnitine translocase induced by partial hepatectomy and fasting. J Biol Chem. 2003 Oct 3;278(40):38796-802. Epub 2003 Jul 25. [12882971 ]
  2. Peluso G, Petillo O, Margarucci S, Grippo P, Melone MA, Tuccillo F, Calvani M: Differential carnitine/acylcarnitine translocase expression defines distinct metabolic signatures in skeletal muscle cells. J Cell Physiol. 2005 May;203(2):439-46. [15515015 ]
  3. Tonazzi A, Giangregorio N, Indiveri C, Palmieri F: Identification by site-directed mutagenesis and chemical modification of three vicinal cysteine residues in rat mitochondrial carnitine/acylcarnitine transporter. J Biol Chem. 2005 May 20;280(20):19607-12. Epub 2005 Mar 9. [15757911 ]
General Function:
Receptor binding
Specific Function:
Beta-oxidation of fatty acids. The highest activity concerns the C6 to C10 chain length substrate. Converts the end product of pristanic acid beta oxidation, 4,8-dimethylnonanoyl-CoA, to its corresponding carnitine ester.
Gene Name:
CROT
Uniprot ID:
Q9UKG9
Molecular Weight:
70177.935 Da
References
  1. Cordente AG, Lopez-Vinas E, Vazquez MI, Swiegers JH, Pretorius IS, Gomez-Puertas P, Hegardt FG, Asins G, Serra D: Redesign of carnitine acetyltransferase specificity by protein engineering. J Biol Chem. 2004 Aug 6;279(32):33899-908. Epub 2004 May 21. [15155769 ]
  2. Cordente AG, Lopez-Vinas E, Vazquez MI, Gomez-Puertas P, Asins G, Serra D, Hegardt FG: Mutagenesis of specific amino acids converts carnitine acetyltransferase into carnitine palmitoyltransferase. Biochemistry. 2006 May 16;45(19):6133-41. [16681386 ]
General Function:
Triglyceride lipase activity
Specific Function:
Involved in the detoxification of xenobiotics and in the activation of ester and amide prodrugs. Hydrolyzes aromatic and aliphatic esters, but has no catalytic activity toward amides or a fatty acyl-CoA ester. Hydrolyzes the methyl ester group of cocaine to form benzoylecgonine. Catalyzes the transesterification of cocaine to form cocaethylene. Displays fatty acid ethyl ester synthase activity, catalyzing the ethyl esterification of oleic acid to ethyloleate.
Gene Name:
CES1
Uniprot ID:
P23141
Molecular Weight:
62520.62 Da
References
  1. Bell FP: Carnitine ester hydrolysis in arteries from normal and cholesterol-fed rabbits and the effects of carnitine esters on arterial microsomal ACAT. Comp Biochem Physiol B. 1984;79(2):125-8. [6509906 ]
General Function:
Acyl carnitine transmembrane transporter activity
Specific Function:
Transports arginine, lysine, homoarginine, methylarginine and, to a much lesser extent, ornithine and histidine. Does not transport carnitine nor acylcarnitines. Functions by both counter-exchange and uniport mechanisms.
Gene Name:
SLC25A29
Uniprot ID:
Q8N8R3
Molecular Weight:
32061.87 Da
References
  1. Sekoguchi E, Sato N, Yasui A, Fukada S, Nimura Y, Aburatani H, Ikeda K, Matsuura A: A novel mitochondrial carnitine-acylcarnitine translocase induced by partial hepatectomy and fasting. J Biol Chem. 2003 Oct 3;278(40):38796-802. Epub 2003 Jul 25. [12882971 ]
General Function:
Peroxidase activity
Specific Function:
Part of the host defense system of polymorphonuclear leukocytes. It is responsible for microbicidal activity against a wide range of organisms. In the stimulated PMN, MPO catalyzes the production of hypohalous acids, primarily hypochlorous acid in physiologic situations, and other toxic intermediates that greatly enhance PMN microbicidal activity.
Gene Name:
MPO
Uniprot ID:
P05164
Molecular Weight:
83867.71 Da
References
  1. Derin N, Agac A, Bayram Z, Asar M, Izgut-Uysal VN: Effects of L-carnitine on neutrophil-mediated ischemia-reperfusion injury in rat stomach. Cell Biochem Funct. 2006 Sep-Oct;24(5):437-42. [16130180 ]
General Function:
Organic cation transmembrane transporter activity
Specific Function:
High affinity carnitine transporter; the uptake is partially sodium-ion dependent. Thought to mediate the L-carnitine secretion mechanism from testis epididymal epithelium into the lumen which is involved in the maturation of spermatozoa. Also transports organic cations such as tetraethylammonium (TEA) and doxorubicin. The uptake of TEA is inhibited by various organic cations. The uptake of doxorubicin is sodium-independent.
Gene Name:
SLC22A16
Uniprot ID:
Q86VW1
Molecular Weight:
64613.58 Da
Binding/Activity Constants
TypeValueAssay TypeAssay Source
Inhibitory30 uMNot AvailableBindingDB 50037268
References
  1. Enomoto A, Wempe MF, Tsuchida H, Shin HJ, Cha SH, Anzai N, Goto A, Sakamoto A, Niwa T, Kanai Y, Anders MW, Endou H: Molecular identification of a novel carnitine transporter specific to human testis. Insights into the mechanism of carnitine recognition. J Biol Chem. 2002 Sep 27;277(39):36262-71. Epub 2002 Jun 27. [12089149 ]
General Function:
Xanthine oxidase activity
Specific Function:
Key enzyme in purine degradation. Catalyzes the oxidation of hypoxanthine to xanthine. Catalyzes the oxidation of xanthine to uric acid. Contributes to the generation of reactive oxygen species. Has also low oxidase activity towards aldehydes (in vitro).
Gene Name:
XDH
Uniprot ID:
P47989
Molecular Weight:
146422.99 Da
References
  1. Di Giacomo C, Latteri F, Fichera C, Sorrenti V, Campisi A, Castorina C, Russo A, Pinturo R, Vanella A: Effect of acetyl-L-carnitine on lipid peroxidation and xanthine oxidase activity in rat skeletal muscle. Neurochem Res. 1993 Nov;18(11):1157-62. [8255367 ]