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DGUOK
Deoxyguanosine kinase, mitochondrial is an enzyme that in humans is encoded by the ''DGUOK'' gene. Function In mammalian cells, the phosphorylation of purine deoxyribonucleosides is mediated predominantly by two deoxyribonucleoside kinases, cytosolic deoxycytidine kinase and mitochondrial deoxyguanosine kinase. The protein encoded by this gene is responsible for phosphorylation of purine deoxyribonucleosides in the mitochondrial matrix. In addition, this protein phosphorylates several purine deoxyribonucleoside analogs used in the treatment of lymphoproliferative disorders, and this phosphorylation is critical for the effectiveness of the analogs. Alternative splice variants encoding different protein isoforms have been described for this gene. Clinical Mutations in this gene have been linked to inherited mitochondrial DNA depletion syndromes, neonatal liver failure, nystagmus and hypotonia Hypotonia is a state of low muscle tone (the amount of tension or resistance to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondrial DNA Depletion Syndrome
Mitochondrial DNA depletion syndrome (MDS or MDDS), or Alper's disease, is any of a group of autosomal recessive disorders that cause a significant drop in mitochondrial DNA in affected tissues. Symptoms can be any combination of myopathic, hepatopathic, or encephalomyopathic. These syndromes affect tissue in the muscle, liver, or both the muscle and brain, respectively. The condition is typically fatal in infancy and early childhood, though some have survived to their teenage years with the myopathic variant and some have survived into adulthood with the SUCLA2 encephalomyopathic variant. There is currently no curative treatment for any form of MDDS, though some preliminary treatments have shown a reduction in symptoms. Signs and symptoms All forms of MDDS are very rare. MDDS causes a wide range of symptoms, which can appear in newborns, infants, children, or adults, depending on the class of MDDS; within each class symptoms are also diverse. In MDDS associated with mutations ... [...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 substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the 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 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 catalytic RNA molecules, called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction ra ... [...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 gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphorylation
In chemistry, phosphorylation is the attachment of a phosphate group to a molecule or an ion. This process and its inverse, dephosphorylation, are common in biology and could be driven by natural selection. Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License. Protein phosphorylation often activates (or deactivates) many enzymes. Glucose Phosphorylation of sugars is often the first stage in their catabolism. Phosphorylation allows cells to accumulate sugars because the phosphate group prevents the molecules from diffusing back across their transporter. Phosphorylation of glucose is a key reaction in sugar metabolism. The chemical equation for the conversion of D-glucose to D-glucose-6-phosphate in the first step of glycolysis is given by :D-glucose + ATP → D-glucose-6-phosphate + ADP : ΔG° = −16.7 kJ/mol (° indicates measurement at standard condition) Hepatic cells are freely permeable to glucose, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deoxyribonucleoside
A deoxyribonucleotide is a nucleotide that contains deoxyribose. They are the monomeric units of the informational biopolymer, deoxyribonucleic acid ( DNA). Each deoxyribonucleotide comprises three parts: a deoxyribose sugar (monosaccharide), a nitrogenous base, and one phosphoryl group. The nitrogenous bases are either purines or pyrimidines, heterocycles whose structures support the specific base-pairing interactions that allow nucleic acids to carry information. The base is always bonded to the 1'-carbon of the deoxyribose, an analog of ribose in which the hydroxyl group of the 2'-carbon is replaced with a hydrogen atom. The third component, the phosphoryl group, attaches to the deoxyribose monomer via the hydroxyl group on the 5'-carbon of the sugar. When deoxyribonucleotides polymerize to form DNA, the phosphate group from one nucleotide will bond to the 3' carbon on another nucleotide, forming a phosphodiester bond via dehydration synthesis. New nucleotides are always added ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deoxynucleoside Kinase
In enzymology, a deoxynucleoside kinase () is an enzyme that catalyzes the chemical reaction :ATP + 2'-deoxynucleoside \rightleftharpoons ADP + 2'-deoxynucleoside 5'-phosphate Thus, the two substrates of this enzyme are ATP and 2'-deoxynucleoside, whereas its two products are ADP and 2'-deoxynucleoside 5'-phosphate. 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:deoxynucleoside 5'-phosphotransferase. Other names in common use include multispecific deoxynucleoside kinase, ms-dNK, multisubstrate deoxyribonucleoside kinase, multifunctional deoxynucleoside kinase, D. melanogaster deoxynucleoside kinase, and Dm-dNK. Structural studies As of late 2007, 5 structures A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Mate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deoxycytidine Kinase
Deoxycytidine kinase (dCK) is an enzyme which is encoded by the ''DCK'' gene in humans. dCK predominantly phosphorylates deoxycytidine (dC) and converts dC into deoxycytidine monophosphate. dCK catalyzes one of the initial steps in the nucleoside salvage pathway and has the potential to phosphorylate other preformed nucleosides, specifically deoxyadenosine (dA) and deoxyguanosine (dG), and convert them into their monophosphate forms. There has been recent biomedical research interest in investigating dCK's potential as a therapeutic target for different types of cancer. Structure dCK is a homodimer where each monomer subunit consists of multiple alpha helices surrounding a beta sheet core. Each subunit includes a nucleotide donor binding site, nucleoside acceptor binding site, nucleotide base sensing loop (240-254 residues), insert region (12-15 residues) that connects helices 2 and 3. dCK has several different protein conformations but its conformation depends on the nucleos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deoxyguanosine Kinase
In enzymology, a deoxyguanosine kinase () is an enzyme that catalyzes the chemical reaction :ATP + deoxyguanosine \rightleftharpoons ADP + dGMP Thus, the two substrates of this enzyme are ATP and deoxyguanosine, whereas its two products are ADP and dGMP. 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:deoxyguanosine 5'-phosphotransferase. Other names in common use include deoxyguanosine kinase (phosphorylating), (dihydroxypropoxymethyl)guanine kinase, 2'-deoxyguanosine kinase, and NTP-deoxyguanosine 5'-phosphotransferase. This enzyme participates in purine metabolism. Structural studies As of late 2007, 4 structures have been solved for this class of enzymes, with PDB accession codes , , , and . Clinical Mutations in this gene have been linked to inherited mitochondrial DNA depletion syndromes, neonatal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondrial
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'' was coined by Carl Benda in 1898. The mitochondrion is popularly nicknamed the "powerhouse of the cell", a phrase coined by Philip Siekevitz in a 1957 article of the same name. Some cells in some multicellular organisms lack mitochondria (for example, mature mammalian red blood cells). A large number of unicellular organisms, such as microsporidia, parabasalids and diplomonads, have reduced or transformed their mitochondria into other structures. One eukaryote, ''Monocercomonoides'', is known to have completely lost its mitochondria, and one multicellular organism, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alternative Splicing
Alternative splicing, or alternative RNA splicing, or differential splicing, is an alternative splicing process during gene expression that allows a single gene to code for multiple proteins. In this process, particular exons of a gene may be included within or excluded from the final, processed messenger RNA (mRNA) produced from that gene. This means the exons are joined in different combinations, leading to different (alternative) mRNA strands. Consequently, the proteins translated from alternatively spliced mRNAs will contain differences in their amino acid sequence and, often, in their biological functions (see Figure). Biologically relevant alternative splicing occurs as a normal phenomenon in eukaryotes, where it increases the number of proteins that can be encoded by the genome. In humans, it is widely believed that ~95% of multi-exonic genes are alternatively spliced to produce functional alternative products from the same gene but many scientists believe that most o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nystagmus
Nystagmus is a condition of involuntary (or voluntary, in some cases) eye movement. Infants can be born with it but more commonly acquire it in infancy or later in life. In many cases it may result in reduced or limited vision. Due to the involuntary movement of the eye, it has been called "dancing eyes". In normal eyesight, while the head rotates about an axis, distant visual images are sustained by rotating eyes in the opposite direction of the respective axis. The semicircular canals in the vestibule of the ear sense angular acceleration, and send signals to the nuclei for eye movement in the brain. From here, a signal is relayed to the extraocular muscles to allow one's gaze to fix on an object as the head moves. Nystagmus occurs when the semicircular canals are stimulated (e.g., by means of the caloric test, or by disease) while the head is stationary. The direction of ocular movement is related to the semicircular canal that is being stimulated. There are two key form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
