Schematic demonstrating mitochondrial fatty acid beta-oxidation and effects of LCHAD deficiency

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. Image File history File links Size of this preview: 800 × 544 pixelsFull resolution (868 × 590 pixel, file size: 58 KB, MIME type: image/jpeg) Schematic diagram of tri-functional mitochondrial protein and mitochondrial fatty acid metabolism, highlighting effects of LCHAD deficiency. ... Image File history File links Size of this preview: 800 × 544 pixelsFull resolution (868 × 590 pixel, file size: 58 KB, MIME type: image/jpeg) Schematic diagram of tri-functional mitochondrial protein and mitochondrial fatty acid metabolism, highlighting effects of LCHAD deficiency. ... In cell biology, a mitochondrion is an organelle found in the cells of most eukaryotes. ... In chemistry, especially biochemistry, a fatty acid is a carboxylic acid often with a long unbranched aliphatic tail (chain), which is either saturated or unsaturated. ... Schematic demonstrating mitochondrial fatty acid beta-oxidation and effects of LCHAD deficiency 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. ... In chemistry, especially biochemistry, a fatty acid is a carboxylic acid often with a long unbranched aliphatic tail (chain), which is either saturated or unsaturated. ... Acyl CoA is a coenzyme involved in the metabolism of fatty acids. ... In cell biology, a mitochondrion is an organelle found in the cells of most eukaryotes. ... Basic structure of a peroxisome Peroxisomes are ubiquitous organelles in eukaryotes that participate in the metabolism of fatty acids and other metabolites. ... Categories: Biochemistry stubs | Thiols ... The citric acid cycle (also known as the tricarboxylic acid cycle, the TCA cycle, or the Krebs cycle) is a series of chemical reactions of central importance in all living cells that utilize oxygen as part of cellular respiration. ...

Occurs in mitochondrial matrix.

Four recurring steps

Once inside the mitochondria, the β-oxidation of fatty acids occurs via four recurring steps:

Description	Diagram	Enzyme	End product
Oxidation by FAD: The first step is the oxidation of the fatty acid by Acyl-CoA-Dehydrogenase. The enzyme catalyzes the formation of a double bond between the C-2 and C-3.		acyl CoA dehydrogenase	trans-Δ2-enoyl-CoA
Hydration: The next step is the hydration of the bond between C-2 and C-3. The reaction is stereospecific, forming only the L isomer.		enoyl CoA hydratase	L-3-hydroxyacyl CoA
Oxidation by NAD+: The third step is the oxidation of L-3-hydroxyacyl CoA by NAD+. This converts the hydroxyl group into a keto group.		L-3-hydroxyacyl CoA dehydrogenase	3-ketoacyl CoA
Thiolysis: The final step is the cleavage of 3-ketoacyl CoA by the thiol group of another molecule of CoA. The thiol is inserted between C-2 and C-3.		Β-ketothiolase	An acetyl CoA molecule, and an acyl CoA molecule, which is two carbons shorter

This process continues until the entire chain is cleaved into acetyl CoA units. For every cycle, the Acyl CoA unit is shortened by two carbon atoms. Concomitantly, one molecule of FADH₂, NADH and acetyl CoA are formed. The most fundamental reactions in chemistry are the redox processes. ... Riboflavin Flavin is a vaginal ring whose biochemical smell is pungent. ... Covalent bonding is a form of chemical bonding characterized by the sharing of one or more pairs of electrons between atoms, in order to produce a mutual attraction, which holds the resultant molecule together. ... Image File history File links Beta-Oxidation1. ... Acyl CoA dehydrogenase is the enzyme used to catalyze the first step of β-oxidation in Fatty acid metabolism. ... In chemistry, hydration is the condition of being combined with water. ... In organic chemistry, a hydration reaction is a chemical reaction in which a hydroxyl group (OH-) and a hydrogen cation (an acidic proton) are added to the two carbon atoms bonded together in the carbon-carbon double bond which makes up an alkene functional group. ... In chemistry, a stereospecific chemical reaction yields different stereoisomeric reaction products from two stereoisomeric reactants depending on the reaction conditions. ... In chemistry, isomers are molecules with the same chemical formula and often with the same kinds of chemical bonds between atoms, but in which the atoms are arranged differently (analogous to a chemical anagram). ... Image File history File links Beta-Oxidation2. ... Enoyl-CoA hydratase is the enzyme used to catalyze the second step of β-oxidation in Fatty acid metabolism. ... The most fundamental reactions in chemistry are the redox processes. ... Nicotinamide adenine dinucleotide (NAD+) Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are two important coenzymes found in cells. ... The most fundamental reactions in chemistry are the redox processes. ... // Hydroxyl group The term hydroxyl group is used to describe the functional group -OH when it is a substituent in an organic compound. ... Keto can refer to: Oxo or Ketone Ceto, a lava mermaid in Greek mythology This is a disambiguation page: a list of articles associated with the same title. ... Image File history File links Beta-Oxidation3. ... The third step of beta oxidation is the oxidation of L-3-hydroxyacyl CoA by NAD+, catalyzed by 3-Hydroxyacyl CoA dehydrogenase. ... Thiolysis is a reaction with a thiol (R-SH) that cleaves one compound into two. ... Sulphydryl // In organic chemistry, a thiol is a compound that contains the functional group composed of a sulfur atom and a hydrogen atom (-SH). ... COA can refer to: Cash on Arrival Cause of action Center of Attention Church of Areaology Ciphertext-only attack model Clowns of America International (COAI), formerly Clowns of America (COA) Coat of Arms College of the Albemarle College of the Atlantic Commission on Athletics ICAO Designation for Continental Airlines Course... Image File history File links Beta-Oxidation4. ... The final step of beta oxidation is the cleavage of 3-ketoacyl CoA by the thiol group of another molecule of CoA. This reaction is catalyzed by Acetyl-CoA C-acyltransferase (or Î’-ketothiolase). ... Acetyl-CoA is an important molecule in metabolism, used in many biochemical reactions. ... Acyl CoA is a coenzyme involved in the metabolism of fatty acids. ...

β-oxidation of unsaturated fatty acids

β-oxidation of unsaturated fatty acids poses a problem since the location of a cis bond can prevent the formation of a trans-δ² bond. These situations are handled by an additional two enzymes.

Whatever the conformation of the hydrocarbon chain, β-oxidation occurs normally until the acyl CoA (because of the presence of a double bond) is not an appropriate substrate for acyl CoA dehydrogenase, or enoyl CoA hydratase:

• If the acyl CoA contains a cis-Δ³ bond, then cis-δ³-Enoyl CoA isomerase will convert the bond to a trans-Δ² bond, which is a regular substrate.

• If the acyl CoA contains a cis-Δ⁴ double bond, then its dehydrogenation yields a 2,4-dienoyl intermediate, which is not a substrate for enoyl CoA hydratase. However, the enzyme 2,4 Dienoyl CoA reductase reduces the intermediate, using NADPH, into trans-Δ³-enoyl CoA. As in the above case, this compound is converted into a suitable intermediate by cis-Δ³-Enoyl CoA isomerase.

To summarize: Enoyl CoA isomerase is an enzyme that catalyzes conversion of cis-double bonds at position 3-4 to trans double bonds at position 2-3. ... 2,4 Dienoyl-CoA reductase is an enzyme on chromosome 8 involved in beta oxidation. ...

• odd numbered double bonds are handled by the isomerase.
• even numbered bonds by the reductase (which creates an odd numbered double bond) and the isomerase.

β-oxidation of odd-numbered chains

Chains with an odd-number of carbons are oxidized in the same manner as even-numbered chains, but the final products are propionyl CoA and acetyl CoA. For other uses, see Carbon (disambiguation). ... Propionyl-CoA is a coenzyme A derivative of propionic acid. ... Acetyl-CoA is an important molecule in metabolism, used in many biochemical reactions. ...

Propionyl CoA is converted into succinyl CoA (which is an intermediate in the citric acid cycle) in a reaction that involves Vitamin B12. Succinyl CoA can then enter the citric acid cycle. Succinyl-CoA (coenzyme A is grey) Succinyl-Coenzyme A, generally abbreviated as Succinyl-CoA is a combination of succinic acid and coenzyme A. Source It is an important intermediate in the citric acid cycle, where is it synthetised from α-Ketoglutarate by α-ketoglutarate dehydrogenase through decarboxylation. ... Overview of the citric acid cycle The citric acid cycle (also known as the tricarboxylic acid cycle, the TCA cycle, or the Krebs cycle, after Hans Adolf Krebs who identified the cycle) is a series of chemical reactions of central importance in all living cells that use oxygen as part... Cobalamin or vitamin B12 is a chemical compound that is also known as cyanocobalamine. ...

Because it cannot be completely metabolized in the citric acid cycle, the products of its partial reaction must be removed in a process called cataplerosis. This allows regeneration of the citric acid cycle intermediates, possibly an important process in certain metabolic diseases. This article is being considered for deletion in accordance with Wikipedias deletion policy. ...

Oxidation in peroxisomes

Fatty acid oxidation also occurs in peroxisomes. However, the oxidation ceases at octanyl CoA. Basic structure of a peroxisome Peroxisomes are ubiquitous organelles in eukaryotes that participate in the metabolism of fatty acids and other metabolites. ... Octanoyl-coenzyme A is the endpoint of beta oxidation in peroxisomes. ...

One significant difference is that oxidation in peroxisomes is not coupled to ATP synthesis. Instead, the high-potential electrons are transferred to O₂, which yields H₂O₂. The enzyme catalase, found exclusively in peroxisomes, converts the hydrogen peroxide into water and oxygen. It is believed that very long chain (C-22)fatty acids undergo initial oxidation in peroxisomes which is followed by mitochondrial oxidation. Peroxisomal oxidation is induced by high fat diet and administration of hypolipidemic drugs like clofibrate. Adenosine 5-triphosphate (ATP) is a multifunctional nucleotide that is most important as a molecular currency of intracellular energy transfer. ... Catalase (human erythrocyte catalase: PDB 1DGF, EC 1. ... R-phrases , , , , S-phrases , , , ,, , , , Flash point Non-flammable Related Compounds Related compounds Water Ozone Hydrazine Except where noted otherwise, data are given for materials in their standard state (at 25 Â°C, 100 kPa) Infobox disclaimer and references Hydrogen peroxide (H2O2) is a very pale blue liquid which appears colourless in... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) pale blue (liquid) Standard atomic weight 15. ...

Energy yield

The ATP yield for every oxidation cycle is 14 ATP, broken down as follows:

For an even-numbered saturated fat (C_2n), n - 1 oxidations are necessary and the final process yields an additional acetyl CoA. In addition, two equivalents of ATP are lost during the activation of the fatty acid. Therefore, the total ATP yield can be stated as: Flavin is also the name of a commune in the Aveyron département, in France Flavin adenine dinucleotide (FAD), upper, reduced FAD (FADH2), lower Flavin is a tricyclic heteronuclear organic ring whose biochemical source is the vitamin riboflavin. ... Nicotinamide adenine dinucleotide (NAD+) Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are two important coenzymes found in cells. ... Acetyl-CoA is an important molecule in metabolism, used in many biochemical reactions. ... Adenosine 5-triphosphate (ATP) is a multifunctional nucleotide that is most important as a molecular currency of intracellular energy transfer. ...

(n - 1) * 14 + 10 - 2 = total ATP

For instance, the ATP yield of palmitate (C₁₆, n = 8) is: It has been suggested that this article or section be merged into Palmitic acid. ...

(8 - 1) * 14 + 10 - 2 = 106 ATP

Represented in table form:

For sources that use the larger ATP production numbers described above, the total would be 129 ATP equivalents per palmitate.

See also

• Fatty acid metabolism
• Krebs cycle
• Omega oxidation

This article or section is in need of attention from an expert on the subject. ... The citric acid cycle (also known as the tricarboxylic acid cycle, the TCA cycle, or the Krebs cycle) is a series of chemical reactions of central importance in all living cells that utilize oxygen as part of cellular respiration. ... Omega-Oxidation is the process by which the omega-carbon of a medium chain fatty acid is oxidized to an acid. ...

External links

• The chemical logic behind fatty acid metabolism at ufp.pt
• JEREMY M. BERG,JOHN L. TYMOCZKO and LUBERT STRYER Biochemistry, 2002
• Animations at brookscole.com