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Fatty Acyl-CoA Esters
Fatty acyl-CoA esters are fatty acid derivatives formed of one fatty acid, a 3'-phospho-Adenosine monophosphate, AMP linked to phosphorylated pantothenic acid (vitamin B5) and cysteamine. Long-chain acyl-CoA esters are substrates for a number of important enzymatic reactions and play a central role in the regulation of metabolism as allosteric regulators of several enzymes. To participate in specific metabolic processes, fatty acids must first be activated by being joined in thioester linkage (R-CO-SCoA) to the -SH group of coenzyme A, where R is a fatty carbon chain. The thioester bond is a high energy bond. The activation reaction normally occurs in the endoplasmic reticulum or the outer mitochondrial membrane. This is an adenosine triphosphate (ATP)-requiring reaction with Fatty-acyl-CoA synthase, fatty acyl-CoA synthase (CoASH), yielding adenosine monophosphate (AMP) and pyrophosphate (PPi): R-COOH + CoASH + ATP \rightleftharpoons R-CO-SCoA + AMP + PPi Different enzymes a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palmitoyl Coenzyme A
In molecular biology, palmitoylation is the Covalent bond, covalent attachment of fatty acids, such as palmitic acid, to cysteine (''S''-palmitoylation) and less frequently to serine and threonine (''O''-palmitoylation) residues of proteins, which are typically lipid bilayer, membrane proteins. The precise function of palmitoylation depends on the particular protein being considered. Palmitoylation enhances the hydrophobicity of proteins and contributes to their membrane association. Palmitoylation also appears to play a significant role in subcellular trafficking of proteins between membrane compartments, as well as in modulating protein–protein interactions. In contrast to prenylation and myristoylation, palmitoylation is usually reversible (because the bond between palmitic acid and protein is often a thioester bond). The reverse reaction in mammalian cells is catalyzed by Acyl-protein thioesterase, acyl-protein thioesterases (APTs) in the cytosol and palmitoyl protein ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondria
A mitochondrion () is an organelle found in the cells of most eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used throughout the cell as a source of chemical energy. They were discovered by Albert von Kölliker in 1857 in the voluntary muscles of insects. The term ''mitochondrion'', meaning a thread-like granule, was coined by Carl Benda in 1898. The mitochondrion is popularly nicknamed the "powerhouse of the cell", a phrase popularized by Philip Siekevitz in a 1957 ''Scientific American'' article of the same name. Some cells in some multicellular organisms lack mitochondria (for example, mature mammalian red blood cells). The multicellular animal '' Henneguya salminicola'' is known to have retained mitochondrion-related organelles despite a complete loss of their mitochondrial genome. A large number of unicellular organisms, such as microspo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiolysis
Thiolysis is a reaction with a thiol (R-SH) that cleaves one compound into two. Thiolysis involves the addition of coenzyme A to one of the products. This reaction is similar to hydrolysis, which involves water instead of a thiol. This reaction is seen in β-oxidation of fatty acids. The depolymerisation of condensed tannin Condensed tannins (proanthocyanidins, polyflavonoid tannins, catechol-type tannins, pyrocatecollic type tannins, non-hydrolyzable tannins or flavolans) are polymers formed by the condensation of flavans. They do not contain sugar residues. They ...s with the use of benzyl mercaptan as nucleophile is also called thiolysis. References Substitution reactions Tannins {{Reaction-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Oxidation
In biochemistry and metabolism, beta oxidation (also β-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. Acetyl-CoA enters the citric acid cycle, generating NADH and FADH2, which are electron carriers used in the electron transport chain. It is named as such because the beta carbon of the fatty acid chain undergoes oxidation and is converted to a carbonyl group to start the cycle all over again. 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. The overall reaction for one cycle of beta oxidation is: :C''n''-acyl-CoA + FAD + NAD''+'' + H''2''O + CoA → C''n''-2-acyl-CoA + FADH''2'' + NADH + H''+'' + acetyl-CoA Activation and membrane transport Free fatty acids cannot penetrate any bi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FADH2
In biochemistry, flavin adenine dinucleotide (FAD) is a redox-active coenzyme associated with various proteins, which is involved with several enzymatic reactions in metabolism. A flavoprotein is a protein that contains a flavin group, which may be in the form of FAD or flavin mononucleotide (FMN). Many flavoproteins are known: components of the succinate dehydrogenase complex, α-ketoglutarate dehydrogenase, and a component of the pyruvate dehydrogenase complex. FAD can exist in four redox states, which are the flavin-N(5)-oxide, quinone, semiquinone, and hydroquinone. FAD is converted between these states by accepting or donating electrons. FAD, in its fully oxidized form, or quinone form, accepts two electrons and two protons to become FADH2 (hydroquinone form). The semiquinone (FADH·) can be formed by either reduction of FAD or oxidation of FADH2 by accepting or donating one electron and one proton, respectively. Some proteins, however, generate and maintain a superoxid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NADH
Nicotinamide adenine dinucleotide (NAD) is a coenzyme central to metabolism. Found in all living cells, NAD is called a dinucleotide because it consists of two nucleotides joined through their phosphate groups. One nucleotide contains an adenine nucleobase and the other, nicotinamide. NAD exists in two forms: an oxidized and reduced form, abbreviated as NAD and NADH (H for hydrogen), respectively. In cellular metabolism, NAD is involved in redox reactions, carrying electrons from one reaction to another, so it is found in two forms: NAD is an oxidizing agent, accepting electrons from other molecules and becoming reduced; with H+, this reaction forms NADH, which can be used as a reducing agent to donate electrons. These electron transfer reactions are the main function of NAD. It is also used in other cellular processes, most notably as a substrate of enzymes in adding or removing chemical groups to or from proteins, in posttranslational modifications. Because of the import ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondrial Matrix
In the mitochondrion, the matrix is the space within the inner membrane. It can also be referred as the mitochondrial fluid. The word "matrix" stems from the fact that this space is viscous, compared to the relatively aqueous cytoplasm. The mitochondrial matrix contains the mitochondrial DNA, ribosomes, soluble enzymes, small organic molecules, nucleotide cofactors, and inorganic ions. /sup> The enzymes in the matrix facilitate reactions responsible for the production of ATP, such as the citric acid cycle, oxidative phosphorylation, oxidation of pyruvate, and the beta oxidation of fatty acids. The composition of the matrix based on its structures and contents produce an environment that allows the anabolic and catabolic pathways to proceed favorably. The electron transport chain and enzymes in the matrix play a large role in the citric acid cycle and oxidative phosphorylation. The citric acid cycle produces NADH and FADH2 through oxidation that will be reduced in oxidative pho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnitine Acyltransferase II
Carnitine O-palmitoyltransferase (also called carnitine palmitoyltransferase) is a mitochondrial transferase enzyme () involved in the metabolism of palmitoylcarnitine into palmitoyl-CoA. A related transferase is carnitine acyltransferase. Molecules Image:Palmitoylcarnitine.PNG , Palmitoylcarnitine Image:Palmitoyl coenzyme A.svg, Palmitoyl CoA Pathway Human forms There are four different forms of CPT in humans: * CPT1A – associated with Carnitine palmitoyltransferase I deficiency * CPT1B * CPT1C * CPT2 – associated with carnitine palmitoyltransferase II deficiency See also * References External links * – Acyltransferases ChoActase / COT / CPT family in PROSITE Choline/Carnitine o-acyltransferase familyin Pfam Pfam is a database of protein families that includes their annotations and multiple sequence alignments generated using hidden Markov models. The latest version of Pfam, 37.0, was released in June 2024 and contains 21,979 families. It is cur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inner Mitochondrial Membrane
The inner mitochondrial membrane (IMM) is the mitochondrial membrane which separates the mitochondrial matrix from the intermembrane space. Structure The structure of the inner mitochondrial membrane is extensively folded and compartmentalized. The numerous invaginations of the membrane are called cristae, separated by crista junctions from the inner boundary membrane juxtaposed to the outer membrane. Cristae significantly increase the total membrane surface area compared to a smooth inner membrane and thereby the available working space for oxidative phosphorylation. The inner membrane creates two compartments. The region between the inner and outer membrane, called the intermembrane space, is largely continuous with the cytosol, while the more sequestered space inside the inner membrane is called the matrix. Cristae For typical liver mitochondria, the area of the inner membrane is about 5 times as large as the outer membrane due to cristae. This ratio is variable and mitocho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnitine
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 from the cytosol into mitochondria to be oxidized for free 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. Generally individuals, including strict vegetarians, synthesize enough L-carnitine in vivo. Carnitine exists as one of two stereoisomers: the two enantiomers -carnitine (''S''-(+)-) and -carnitine (''R''-(−)-). Both are biologically active, but only -carnitine naturally occurs in animals, and -carnitine is toxic as it inhibits the activity of the -form. At room temperature, pure carnitine is a whiteish powder, and a water-soluble zwitterion with relatively low toxicity. Derived from amino acids, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antiporter
An antiporter (also called exchanger or counter-transporter) is an integral membrane protein that uses secondary active transport to move two or more molecules in opposite directions across a phospholipid membrane. It is a type of cotransporter, which means that uses the Exergonic reaction, energetically favorable movement of one molecule down its electrochemical gradient to power the Endergonic reaction, energetically unfavorable movement of another molecule up its electrochemical gradient. This is in contrast to symporters, which are another type of cotransporter that moves two or more ions in the same direction, and primary active transport, which is directly powered by Adenosine triphosphate, ATP. Transport may involve one or more of each type of solute. For example, the Sodium-calcium exchanger, Na+/Ca2+ exchanger, found in the plasma membrane of many cells, moves three sodium ions in one direction, and one calcium ion in the other. As with sodium in this example, antiport ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outer Mitochondrial Membrane
A mitochondrion () is an organelle found in the cells of most eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used throughout the cell as a source of chemical energy. They were discovered by Albert von Kölliker in 1857 in the voluntary muscles of insects. The term ''mitochondrion'', meaning a thread-like granule, was coined by Carl Benda in 1898. The mitochondrion is popularly nicknamed the "powerhouse of the cell", a phrase popularized by Philip Siekevitz in a 1957 ''Scientific American'' article of the same name. Some cells in some multicellular organisms lack mitochondria (for example, mature mammalian red blood cells). The multicellular animal '' Henneguya salminicola'' is known to have retained mitochondrion-related organelles despite a complete loss of their mitochondrial genome. A large number of unicellular organisms, such as microsporidia, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
