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COASY
Bifunctional coenzyme A synthase is an enzyme that in mammals is encoded by the ''COASY'' gene that catalyses the synthesis of coenzyme A from 4'- phosphopantetheine. Function COASY is an enzyme that catalyzes the last two steps in the synthesis of coenzyme A from vitamin B5 (pantothenic acid). The primary substrate is 4'- phosphopantetheine and COASY is a bifunctional enzyme in this pathway: * 4′-Phosphopantetheine is adenylated to form dephospho-CoA by the enzyme phosphopantetheine adenylyl-transferase (PPAT; CoaD) * Next, dephospho-CoA is phosphorylated to coenzyme A by the enzyme dephospho-CoA kinase (DPCK; CoaE) In mammals this is a single enzyme, but in organisms including yeast and bacteria these enzymes are encoded by separate genes. Interactions COASY has been shown to interact with P70-S6 Kinase 1. In 2009, COASY has also been implicated in PI3K signaling, as it was shown to interact with a regulatory subunit of PI3K. Clinical significance Loss of function m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coenzyme A
Coenzyme A (CoA, SHCoA, CoASH) is a coenzyme, notable for its role in the synthesis and oxidation of fatty acids, and the oxidation of pyruvate in the citric acid cycle. All genomes sequenced to date encode enzymes that use coenzyme A as a substrate, and around 4% of cellular enzymes use it (or a thioester) as a substrate. In humans, CoA biosynthesis requires cysteine, pantothenate (vitamin B5), and adenosine triphosphate (ATP). In its acetyl form, coenzyme A is a highly versatile molecule, serving metabolic functions in both the anabolic and catabolic pathways. Acetyl-CoA is utilised in the post-translational regulation and allosteric regulation of pyruvate dehydrogenase and carboxylase to maintain and support the partition of pyruvate synthesis and degradation. Discovery of structure Coenzyme A was identified by Fritz Lipmann in 1946, who also later gave it its name. Its structure was determined during the early 1950s at the Lister Institute, London, together by L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurodegeneration With Brain Iron Accumulation
Neurodegeneration with brain iron accumulation is a heterogenous group of inherited neurodegenerative diseases, still under research, in which iron accumulates in the basal ganglia, either resulting in progressive dystonia, Parkinsonism, spasticity, optic atrophy, retinal degeneration, neuropsychiatric, or diverse neurologic abnormalities. Some of the NBIA disorders have also been associated with several genes in synapse and lipid metabolism related pathways. NBIA is not one disease but an entire group of disorders, characterized by an accumulation of brain iron, sometimes in the presence of axonal spheroids in the central nervous system. Iron accumulation can occur anywhere in the brain, with accumulation typically occurring in globus pallidus, substantia nigra, pars reticula, striatum and cerebellar dentate nuclei. Symptoms can include various movement disorders, neuropsychiatric issues, seizures, visual disturbances, and cognitive decline, usually in different combinations. 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
P70-S6 Kinase 1
Ribosomal protein S6 kinase beta-1 (S6K1), also known as p70S6 kinase (p70S6K, p70-S6K), is an enzyme (specifically, a protein kinase) that in humans is encoded by the ''RPS6KB1'' gene. It is a serine/threonine kinase that acts downstream of PIP3 and phosphoinositide-dependent kinase-1 in the PI3 kinase pathway. As the name suggests, its target substrate is the S6 ribosomal protein. Phosphorylation of S6 induces protein synthesis at the ribosome. The phosphorylation of p70S6K at threonine 389 has been used as a hallmark of activation by mTOR and correlated with autophagy inhibition in various situations. However, several recent studies suggest that the activity of p70S6K plays a more positive role in the increase of autophagy. Function This gene encodes a member of the S6K family of serine/threonine kinases, which phosphorylate several residues of the S6 ribosomal protein. The kinase activity of this protein leads to an increase in protein synthesis and cell proliferation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecules known as product (chemistry), products. Almost all metabolism, metabolic processes in the cell (biology), cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme, pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts are Ribozyme, catalytic RNA molecules, called ribozymes. Enzymes' Chemical specificity, specific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphopantetheine
Phosphopantetheine, also known as 4'-phosphopantetheine, is a prosthetic group of several acyl carrier proteins including the acyl carrier proteins (ACP) of fatty acid synthases, ACPs of polyketide synthases, the peptidyl carrier proteins (PCP), as well as aryl carrier proteins (ArCP) of nonribosomal peptide synthetases (NRPS). It is also present in formyltetrahydrofolate dehydrogenase. Subsequent to the expression of the ''apo'' acyl carrier protein, 4'-phosphopantetheine moiety is attached to a serine residue. The coupling involves formation of a phosphodiester linkage. This coupling is mediated by acyl carrier protein synthase (ACPS), a 4'-phosphopantetheinyl transferase. Phosphopantetheine prosthetic group covalently links to the acyl group via a high energy thioester bond. The flexibility and length of the phosphopantetheine chain (approximately 2 nm) allows the covalently tethered intermediates to access spatially distinct enzyme-active sites. This accessibility inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pantothenic Acid
Pantothenic acid, also called vitamin B5 is a water-soluble B vitamin and therefore an essential nutrient. All animals require pantothenic acid in order to synthesize coenzyme A (CoA) – essential for fatty acid metabolism – as well as to, in general, synthesize and metabolize proteins, carbohydrates, and fats. Pantothenic acid is the combination of pantoic acid and β-alanine. Its name derives from the Greek ''pantos'', meaning "from everywhere", as minimally, at least small quantities of pantothenic acid are found in nearly every food. Human deficiency is very rare. As a dietary supplement or animal feed ingredient, the form commonly used is calcium pantothenate because of chemical stability, and hence long product shelf life, compared to sodium pantothenate or free pantothenic acid. Definition Pantothenic acid is a water-soluble vitamin, one of the B vitamins. It is synthesized from the amino acid β-alanine and pantoic acid (see biosynthesis and structure of coen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pantetheine-phosphate Adenylyltransferase
In enzymology, a pantetheine-phosphate adenylyltransferase () is an enzyme that catalyzes the chemical reaction :ATP + 4'-Phosphopantetheine\rightleftharpoons diphosphate + 3'-dephospho-CoA Thus, the two substrates of this enzyme are ATP and 4'-Phosphopantetheine, whereas its two products are diphosphate and 3'-dephospho-CoA. This enzyme belongs to the family of transferases, specifically those transferring phosphorus-containing nucleotide groups ( nucleotidyltransferases). The systematic name of this enzyme class is ATP:pantetheine-4'-phosphate adenylyltransferase. Other names in common use include dephospho-CoA pyrophosphorylase, pantetheine phosphate adenylyltransferase, dephospho-coenzyme A pyrophosphorylase, and 3'-dephospho-CoA pyrophosphorylase. This enzyme participates in pantothenate and coa biosynthesis Pantothenic acid, also called vitamin B5 is a water-soluble B vitamin and therefore an essential nutrient. All animals require pantothenic acid in order to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dephospho-CoA Kinase
In enzymology, a dephospho-CoA kinase () is an enzyme that catalyzes the chemical reaction :ATP + dephospho-CoA \rightleftharpoons ADP + CoA Thus, the two substrates of this enzyme are ATP and dephospho-CoA, whereas its two products are ADP and CoA. This enzyme belongs to the family of transferases, specifically those transferring phosphorus-containing groups (phosphotransferases) with an alcohol group as acceptor. The systematic name of this enzyme class is ATP:dephospho-CoA 3'-phosphotransferase. Other names in common use include dephosphocoenzyme A kinase (phosphorylating), 3'-dephospho-CoA kinase, and dephosphocoenzyme A kinase. This enzyme participates in pantothenate and coa biosynthesis Pantothenic acid, also called vitamin B5 is a water-soluble B vitamin and therefore an essential nutrient. All animals require pantothenic acid in order to synthesize coenzyme A (CoA) – essential for fatty acid metabolism – as well as to, .... Structural studies As of lat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PI3K
Phosphoinositide 3-kinases (PI3Ks), also called phosphatidylinositol 3-kinases, are a family of enzymes involved in cellular functions such as cell growth, proliferation, differentiation, motility, survival and intracellular trafficking, which in turn are involved in cancer. PI3Ks are a family of related intracellular signal transducer enzymes capable of phosphorylating the 3 position hydroxyl group of the inositol ring of phosphatidylinositol (PtdIns). The pathway, with oncogene PIK3CA and tumor suppressor gene PTEN, is implicated in the sensitivity of cancer tumors to insulin and IGF1, and in calorie restriction. Discovery The discovery of PI3Ks by Lewis Cantley and colleagues began with their identification of a previously unknown phosphoinositide kinase associated with the polyoma middle T protein. They observed unique substrate specificity and chromatographic properties of the products of the lipid kinase, leading to the discovery that this phosphoinositide kinase had th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
