Carnitine O-palmitoyltransferase

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Choline/Carnitine o-acyltransferase
PDB 1ndi EBI.jpg
Structure of carnitine acetyltransferase. [1]
Identifiers
SymbolCarn_acyltransf
Pfam PF00755
Pfam clan CL0149
InterPro IPR000542
PROSITE PDOC00402
SCOP2 1ndi / SCOPe / SUPFAM
OPM superfamily 83
OPM protein 2h3u

Carnitine O-palmitoyltransferase (also called carnitine palmitoyltransferase) is a mitochondrial transferase enzyme (EC 2.3.1.21) involved in the metabolism of palmitoylcarnitine into palmitoyl-CoA. A related transferase is carnitine acyltransferase.

Contents

Molecules

Pathway

Human forms

There are four different forms of CPT in humans:

See also

Related Research Articles

Carnitine Chemical compound

Carnitine is a quaternary ammonium compound involved in metabolism in most mammals, plants, and some bacteria. In support of energy metabolism, carnitine transports long-chain fatty acids into mitochondria to be oxidized for energy production, and also participates in removing products of metabolism from cells. Given its key metabolic roles, carnitine is concentrated in tissues like skeletal and cardiac muscle that metabolize fatty acids as an energy source. Healthy individuals, including strict vegetarians, synthesize enough L-carnitine in vivo to not require supplementation.

Beta oxidation Process of fatty acid breakdown

In biochemistry and metabolism, beta-oxidation is the catabolic process by which fatty acid molecules are broken down in the cytosol in prokaryotes and in the mitochondria in eukaryotes to generate acetyl-CoA, which enters the citric acid cycle, and NADH and FADH2, which are co-enzymes used in the electron transport chain. It is named as such because the beta carbon of the fatty acid undergoes oxidation to a carbonyl group. Beta-oxidation is primarily facilitated by the mitochondrial trifunctional protein, an enzyme complex associated with the inner mitochondrial membrane, although very long chain fatty acids are oxidized in peroxisomes.

Inborn error of lipid metabolism Medical condition

Numerous genetic disorders are caused by errors in fatty acid metabolism. These disorders may be described as fatty oxidation disorders or as a lipid storage disorders, and are any one of several inborn errors of metabolism that result from enzyme defects affecting the ability of the body to oxidize fatty acids in order to produce energy within muscles, liver, and other cell types.

Carnitine palmitoyltransferase I deficiency Medical condition

Carnitine palmitoyltransferase I deficiency is a rare metabolic disorder that prevents the body from converting certain fats called long-chain fatty acids into energy, particularly during periods without food. It is caused by a mutation in CPT1A on chromosome 11.

Carnitine palmitoyltransferase II deficiency Medical condition

Carnitine palmitoyltransferase II deficiency is an autosomal recessively inherited genetic metabolic disorder characterized by an enzymatic defect that prevents long-chain fatty acids from being transported into the mitochondria for utilization as an energy source. The disorder presents in one of three clinical forms: lethal neonatal, severe infantile hepatocardiomuscular and myopathic.

Palmitoylcarnitine Chemical compound

Palmitoylcarnitine is an ester derivative of carnitine involved in the metabolism of fatty acids.

Acyl-CoA

Acyl-CoA is a group of coenzymes that metabolize fatty acids. Acyl-CoA's are susceptible to beta oxidation, forming, ultimately, acetyl-CoA. The acetyl-CoA enters the citric acid cycle, eventually forming several equivalents of ATP. In this way, fats are converted to ATP, the universal biochemical energy carrier.

Fatty acid degradation is the process in which fatty acids are broken down into their metabolites, in the end generating acetyl-CoA, the entry molecule for the citric acid cycle, the main energy supply of animals. It includes three major steps:

Palmitoyl-CoA is an acyl-CoA thioester. It is an "activated" form of palmitic acid and can be transported into the mitochondrial matrix by the carnitine shuttle system, and once inside can participate in β-oxidation. Alternatively, palmitoyl-CoA is used as a substrate in the biosynthesis of sphingosine.

Carnitine palmitoyltransferase II

Carnitine O-palmitoyltransferase 2, mitochondrial is an enzyme that in humans is encoded by the CPT2 gene.

Carnitine palmitoyltransferase I

Carnitine palmitoyltransferase I (CPT1) also known as carnitine acyltransferase I, CPTI, CAT1, CoA:carnitine acyl transferase (CCAT), or palmitoylCoA transferase I, is a mitochondrial enzyme responsible for the formation of acyl carnitines by catalyzing the transfer of the acyl group of a long-chain fatty acyl-CoA from coenzyme A to l-carnitine. The product is often Palmitoylcarnitine, but other fatty acids may also be substrates. It is part of a family of enzymes called carnitine acyltransferases. This "preparation" allows for subsequent movement of the acyl carnitine from the cytosol into the intermembrane space of mitochondria.

In enzymology, an acylcarnitine hydrolase (EC 3.1.1.28) is an enzyme that catalyzes the chemical reaction

In enzymology, a palmitoyl-CoA hydrolase is an enzyme in the family of hydrolases that specifically acts on thioester bonds. It catalyzes the hydrolysis of long chain fatty acyl thioesters of acyl carrier protein or coenzyme A to form free fatty acid and the respective thiol.

Carnitine O-acetyltransferase Enzyme

Carnitine O-acetyltransferase also called carnitine acetyltransferase is an enzyme that encoded by the CRAT gene that catalyzes the chemical reaction

In enzymology, a carnitine O-octanoyltransferase is an enzyme that catalyzes the chemical reaction

In enzymology, an ecdysone O-acyltransferase is an enzyme that catalyzes the chemical reaction

In enzymology, a glycoprotein N-palmitoyltransferase is an enzyme that catalyzes the chemical reaction

In enzymology, a [myelin-proteolipid] O-palmitoyltransferase is an enzyme that catalyzes the chemical reaction

Fatty-acid metabolism disorder Medical condition

A broad classification for genetic disorders that result from an inability of the body to produce or utilize one enzyme that is required to oxidize fatty acids. The enzyme can be missing or improperly constructed, resulting in it not working. This leaves the body unable to produce energy within the liver and muscles from fatty acid sources.

DHHC domain

In molecular biology the DHHC domain is a protein domain that acts as an enzyme, which adds a palmitoyl chemical group to proteins in order to anchor them to cell membranes. The DHHC domain was discovered in 1999 and named after a conserved sequence motif found in its protein sequence. Roth and colleagues showed that the yeast Akr1p protein could palmitoylate Yck2p in vitro and inferred that the DHHC domain defined a large family of palmitoyltransferases. In mammals twenty three members of this family have been identified and their substrate specificities investigated. Some members of the family such as ZDHHC3 and ZDHHC7 enhance palmitoylation of proteins such as PSD-95, SNAP-25, GAP43, Gαs. Others such as ZDHHC9 showed specificity only toward the H-Ras protein. However, a recent study questions the involvement of classical enzyme-substrate recognition and specificity in the palmitoylation reaction. Several members of the family have been implicated in human diseases.

References

  1. Jogl G, Tong L (January 2003). "Crystal structure of carnitine acetyltransferase and implications for the catalytic mechanism and fatty acid transport". Cell. 112 (1): 113–22. doi: 10.1016/S0092-8674(02)01228-X . PMID   12526798.