(R)-carnitine transport
Definition
Target type: biologicalprocess
The directed movement of a (R)-carnitine into, out of or within a cell, or between cells, by means of some agent such as a transporter or pore. [GOC:TermGenie, PMID:16365044, PMID:20357772, PMID:20829798]
**(R)-Carnitine Transport**
**(R)-Carnitine** is a quaternary ammonium compound essential for the transport of long-chain fatty acids into the mitochondria for beta-oxidation, the primary energy-producing pathway for these molecules. This process is critical for energy generation, particularly during periods of fasting or intense physical activity.
**(1) Cellular Uptake:**
* **Carnitine uptake** occurs primarily in the small intestine, where it is absorbed from the diet or supplemented forms.
* It also enters cells through a **sodium-dependent carnitine transporter** (OCTN2) found on the plasma membrane of many tissues.
* **OCTN2** is a multispecific transporter that also handles other compounds like choline and butyrate.
* Once inside the cell, (R)-carnitine can be further transported into the mitochondria.
**(2) Mitochondrial Transport:**
* The **mitochondrial membrane** is impermeable to long-chain fatty acids.
* **Carnitine acyltransferases** (CATs) play a key role in shuttling fatty acids across this membrane.
* **CAT1** is located on the outer mitochondrial membrane and catalyzes the formation of **acylcarnitine** from fatty acyl-CoA and carnitine.
* **Acylcarnitine** is then transported into the mitochondrial matrix by the **carnitine/acylcarnitine translocase** (CACT), which is located on the inner mitochondrial membrane.
* Once inside the matrix, **CAT2** hydrolyzes acylcarnitine, releasing free carnitine and fatty acyl-CoA, which can then enter beta-oxidation.
**(3) Regulation and Importance:**
* The transport of (R)-carnitine is tightly regulated by the availability of carnitine, the concentration of fatty acids, and the energy demands of the cell.
* **Deficiency** in carnitine can lead to impaired fatty acid oxidation and energy production, with consequences for muscle function, energy levels, and overall metabolism.
* **Genetic disorders** affecting the expression or function of OCTN2, CATs, or CACT can also disrupt carnitine transport and lead to various metabolic problems.
**Summary:**
(R)-carnitine transport is a crucial process for energy production by facilitating the entry of long-chain fatty acids into mitochondria for beta-oxidation. This process involves cellular uptake, mitochondrial transport, and regulation by specific transporters and enzymes. Maintaining adequate carnitine levels is important for optimal energy metabolism and overall health.'
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Proteins (1)
| Protein | Definition | Taxonomy |
|---|---|---|
| Solute carrier family 22 member 5 | An organic cation/carnitine transporter 2 that is encoded in the genome of human. [PRO:DNx, UniProtKB:O76082] | Homo sapiens (human) |
Compounds (4)
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| carnitine | amino-acid betaine | human metabolite; mouse metabolite | |
| cephaloridine | cefaloridine : A cephalosporin compound having pyridinium-1-ylmethyl and 2-thienylacetamido side-groups. A first-generation semisynthetic derivative of cephalosporin C. Cephaloridine: A cephalosporin antibiotic. | beta-lactam antibiotic allergen; cephalosporin; semisynthetic derivative | antibacterial drug |
| cefepime | cefepime : A cephalosporin bearing (1-methylpyrrolidinium-1-yl)methyl and (2Z)-2-(2-amino-1,3-thiazol-4-yl)-2-(methoxyimino)acetamido groups at positions 3 and 7, respectively, of the cephem skeleton. Cefepime: A fourth-generation cephalosporin antibacterial agent that is used in the treatment of infections, including those of the abdomen, urinary tract, respiratory tract, and skin. It is effective against PSEUDOMONAS AERUGINOSA and may also be used in the empiric treatment of FEBRILE NEUTROPENIA. | cephalosporin; oxime O-ether | antibacterial drug |
| acetylcarnitine | O-acetyl-L-carnitine : An O-acyl-L-carnitine where the acyl group specified is acetyl. It facilitates movement of acetyl-CoA into the matrices of mammalian mitochondria during the oxidation of fatty acids. | O-acetylcarnitine; saturated fatty acyl-L-carnitine | human metabolite; Saccharomyces cerevisiae metabolite |