What Is Carnitine?
Carnitine is an organic compound classified as a hydroxy acid and a quaternary ammonium compound.
It has the chemical formula C7H15NO3, and is classified as a hydroxyl acid because it has hydroxy and carboxyl groups in the molecule, and also has a quaternary ammonium ion structure. Its registration numbers are 406-76-8 for the DL-carnitine raceminc mixture and 541-15-1 for L-carnitine.
It has a molecular weight of 161.199, a density of 0.64 g/㎠, a melting point of 190-195°C, and is a crystalline powder at room temperature. It is white to yellowish-brown. It is soluble in water and ethanol, but virtually insoluble in acetone.
L-carnitine is abundant in muscle cells and is an essential compound for lipid metabolism; when L-carnitine is bound to fatty acids and transported to the mitochondria, lipids are burned and utilized as energy in the body.
Uses of Carnitine
In the human body, carnitine is a substance involved in lipid metabolism. For this reason, it has been widely used as a dietary supplement in recent years. However, healthy children and adults can synthesize enough carnitine in their liver and kidneys to meet their daily needs.
On the other hand, the substance is approved as a drug for carnitine deficiency, and is administered orally or intravenously. Causes of carnitine deficiency include insufficient intake due to diet and other factors, deficient biosynthesis caused by renal or hepatic insufficiency, excessive loss due to dialysis or diarrhea, and side effects of pharmaceuticals.
As an in vitro substance, carnitine is also used as a reagent for research and development in fields such as biochemistry.
Characteristics of Carnitine
Carnitine has a pair of mirror isomers because the chiral center of carnitine is the carbon at position 3, i.e., the carbon to which the hydroxyl group is attached. When distinguishing between the mirror isomers, they are often distinguished as D-carnitine and L-carnitine.
The racemic mixture of equal amounts of these isomers is often referred to as DL-carnitine.
Types of Carnitine
Carnitine is sold as a dietary supplement, a drug, and a reagent for research and development. As a dietary supplement, L-carnitine is sold by many manufacturers and is available in pill form.
As a pharmaceutical product, L-carnitine is prescribed for carnitine deficiency, and its generic name is levocarnitine (L-carnitine). It is available in tablet and oral solution formulations. In addition to free levocarnitine, levocarnitine-chloride tablets also exist, so care should be taken not to confuse the two.
In addition to free L-carnitine, it is often sold as L-carnitine hydrochloride or racemic DL-carnitine hydrochloride as an R&D reagent. The hydrochloride salt is the result of purification conditions during commercialization. It is a reagent product that can be stored at room temperature and is available in a variety of capacities, including 10 mg, 1 g, 5 g, 25 g, and 100 g .
Other Information on Carnitine
1. Biosynthesis of Carnitine
In the body, carnitine is biosynthesized from the essential amino acids lysine and methionine. First, methionine is converted to S-adenosylmethionine.Methyltransferase transfers the methyl group of S-adenosylmethionine to an amino group on the side chain of lysine, and the quaternary ammonium portion of carnitine is synthesized. In addition, another enzymatic reaction stereo selectively adds a hydroxyl group to the side chain of lysine to construct the molecular skeleton.
2. Carnitine Deficiency
There are two types of carnitine deficiency disorders: the first is an inherited disorder of the cellular carnitine transport system. In this case, symptoms of cardiomyopathy, skeletal muscle weakness, and hypoglycemia usually appear by age 5.
The second is a carnitine deficiency caused by a specific disease (such as chronic renal failure) or under specific conditions (such as the use of certain antimicrobials). In these cases, there is a decrease in carnitine absorption or an increase in its elimination.
Carnitine preparations are prescribed to treat these deficiencies.