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NMNAT1
Nicotinamide mononucleotide adenylyltransferase 1 (NMNAT1) is an enzyme that in humans is encoded by the ''nmnat1'' gene. It is a member of the nicotinamide-nucleotide adenylyltransferases (NMNATs) which catalyze nicotinamide adenine dinucleotide (NAD) synthesis. Function The coenzyme NAD and its derivatives are involved in hundreds of metabolic redox reactions and are utilized in protein ADP-ribosylation, histone deacetylation, and in some Ca2+ signaling pathways. NMNAT (EC 2.7.7.1) is a central enzyme in NAD biosynthesis, catalyzing the condensation of nicotinamide mononucleotide (NMN) or nicotinic acid mononucleotide (NaMN) with the AMP moiety of ATP to form NAD or NaAD. NMNAT1 is the most widely expressed of three orthologous genes with nicotinamide-nucleotide adenylyltransferase (NMNAT) activity. Genetically engineered mice lacking NMNAT1 die during early embryogenesis, indicating a critical role of this gene in organismal viability. In contrast, mice lacking NMNAT2, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leber's Congenital Amaurosis
Leber congenital amaurosis (LCA) is a rare inherited eye disease that appears at birth or in the first few months of life. It affects about 1 in 40,000 newborns. LCA was first described by Theodor Leber in the 19th century. It should not be confused with Leber's hereditary optic neuropathy, which is a different disease also described by Theodor Leber. One form of LCA was successfully treated with gene therapy in 2008. Signs and symptoms The term congenital refers to a condition present from birth (not acquired) and amaurosis refers to a loss of vision not associated with a lesion. However, beyond these general descriptions, the presentation of LCA can vary, because it is associated with multiple genes. LCA is typically characterized by nystagmus, sluggish or absent pupillary responses, and severe vision loss or blindness. Genetics It is usually autosomal recessive; however, importantly for family planning, it is sometimes autosomal dominant. It is a disorder thought to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SARM1
Sterile alpha and TIR motif containing 1 Is an enzyme that in humans is encoded by the ''SARM1'' gene. It is the most evolutionarily conserved member of the Toll/Interleukin receptor-1 (TIR) family. SARM1's TIR domain has intrinsic NADase enzymatic activity that is highly conserved from archaea, plants, nematode worms, fruit flies, and humans. In mammals, SARM1 is highly expressed in neurons, where it resides in both cell bodies and axons, and can be associated with mitochondria. Function While SARM1 has been studied as a Toll-like receptor adaptor protein in an immune context, its most well-studied function in mammals is as a sensor of metabolic stress and an executioner of neuronal cell body and axon death. Because SARM1 is highly expressed in the nervous system, most studies of SARM1 focus on neuron degeneration, but some SARM1 can be found in other tissues, notably macrophages and T cells. By generating cADPR or NAADP, SARM1 may function as a Ca2+-signaling enzyme sim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nicotinamide-nucleotide Adenylyltransferase
In enzymology, nicotinamide-nucleotide adenylyltransferase (NMNAT) () are enzymes that catalyzes the chemical reaction :ATP + nicotinamide mononucleotide \rightleftharpoons diphosphate + NAD+ Thus, the two substrates of this enzyme are ATP and nicotinamide mononucleotide (NMN), whereas its two products are diphosphate and NAD+. This enzyme participates in nicotinate and nicotinamide metabolism. Humans have three protein isoforms: NMNAT1 (widespread), NMNAT2 (predominantly in brain), and NMNAT3 (highest in liver, heart, skeletal muscle, and erythrocytes). Mutations in the ''NMNAT1'' gene lead to the LCA9 form of Leber congenital amaurosis. Mutations in ''NMNAT2'' or ''NMNAT3'' genes are not known to cause any human disease. NMNAT2 is critical for neurons: loss of NMNAT2 is associated with neurodegeneration. All NMNAT isoforms reportedly decline with age. Belongs to This enzyme belongs to the family of transferases, specifically those transferring phosphorus-containing nucle ... [...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] |
Chemotherapy
Chemotherapy (often abbreviated to chemo and sometimes CTX or CTx) is a type of cancer treatment that uses one or more anti-cancer drugs (chemotherapeutic agents or alkylating agents) as part of a standardized chemotherapy regimen. Chemotherapy may be given with a curative intent (which almost always involves combinations of drugs) or it may aim to prolong life or to reduce symptoms ( palliative chemotherapy). Chemotherapy is one of the major categories of the medical discipline specifically devoted to pharmacotherapy for cancer, which is called ''medical oncology''. The term ''chemotherapy'' has come to connote non-specific usage of intracellular poisons to inhibit mitosis (cell division) or induce DNA damage, which is why inhibition of DNA repair can augment chemotherapy. The connotation of the word chemotherapy excludes more selective agents that block extracellular signals (signal transduction). The development of therapies with specific molecular or genetic targets, wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
De Novo Synthesis
In chemistry, ''de novo'' synthesis () refers to the synthesis of complex molecules from simple molecules such as sugars or amino acids, as opposed to recycling after partial degradation. For example, nucleotides are not needed in the diet as they can be constructed from small precursor molecules such as formate and aspartate. Methionine, on the other hand, is needed in the diet because while it can be degraded to and then regenerated from homocysteine, it cannot be synthesized ''de novo''. Nucleotide ''De novo'' pathways of nucleotides do not use free bases: adenine (abbreviated as A), guanine (G), cytosine (C), thymine (T), or uracil (U). The purine ring is built up one atom or a few atoms at a time and attached to ribose throughout the process. Pyrimidine ring is synthesized as orotate and attached to ribose phosphate and later converted to common pyrimidine nucleotides. Cholesterol Cholesterol is an essential structural component of animal cell membranes. Cholestero ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Q26840015
Q, or q, is the seventeenth letter of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is pronounced , most commonly spelled ''cue'', but also ''kew'', ''kue'' and ''que''. History The Semitic sound value of Qôp was (voiceless uvular stop), and the form of the letter could have been based on the eye of a needle, a knot, or even a monkey with its tail hanging down. is a sound common to Semitic languages, but not found in many European languages. Some have even suggested that the form of the letter Q is even more ancient: it could have originated from Egyptian hieroglyphics. In an early form of Ancient Greek, qoppa (Ϙ) probably came to represent several labialized velar stops, among them and . As a result of later sound shifts, these sounds in Greek changed to and respectively. Therefore, qoppa was transformed into two letters: qoppa, which stood for the number 90, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Current Opinion In Genetics & Development
''Current Opinion'' is a collection of review journals on various disciplines of the life sciences. They were acquired by Elsevier in 1997. Each issue of each journal, which all are published bimonthly, contains one or more themed sections edited by scientists who specialise in the field and invite authors to contribute reviews aimed at experts and non-specialists. Each journal aims to cover all the major recent advances in its topic area, and to direct readers to the most important original research. Journals See also * Current Opinion (Lippincott Williams & Wilkins) ''Current Opinion'' is a series of medical journals published by Wolters Kluwer imprint Lippincott Williams & Wilkins. Wolters Kluwer acquired the journals from the Thomson Organisation International Thomson Organization (ITO) was a holding comp ... References External links * {{Reed Elsevier Elsevier imprints Elsevier academic journals Publishing companies established in 1990 Review journals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dactinomycin
Dactinomycin, also known as actinomycin D, is a chemotherapy medication used to treat a number of types of cancer. This includes Wilms tumor, rhabdomyosarcoma, Ewing's sarcoma, trophoblastic neoplasm, testicular cancer, and certain types of ovarian cancer. It is given by injection into a vein. Most people develop side effects. Common side effects include bone marrow suppression, vomiting, mouth ulcers, hair loss, liver problems, infections, and muscle pains. Other serious side effects include future cancers, allergic reactions, and tissue death at the site of injection. Use in pregnancy may harm the baby. Dactinomycin is in the cytotoxic antibiotic family of medications. It is believed to work by blocking the creation of RNA. Dactinomycin was approved for medical use in the United States in 1964. It is on the World Health Organization's List of Essential Medicines. Medical use Actinomycin is a clear, yellowish liquid administered intravenously and most commonly used in tre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poly (ADP-ribose) Polymerase
Poly (ADP-ribose) polymerase (PARP) is a family of proteins involved in a number of cellular processes such as DNA repair, genomic stability, and programmed cell death. Members of PARP family The PARP family comprises 17 members (10 putative). They vary greatly in structure and function within the cell. * ''PARP1'', '' PARP2'', VPARP (''PARP4''), Tankyrase-1 and -2 (PARP-5a or ''TNKS'', and PARP-5b or ''TNKS2'') have a confirmed PARP activity. * Others include '' PARP3'', , '' TIPARP'' (or "PARP7"), '' PARP8'', , '' PARP10'', , '' PARP12'', , , and '' PARP16''. Structure PARP is composed of four domains of interest: a DNA-binding domain, a caspase-cleaved domain (see below), an auto-modification domain, and a catalytic domain. The DNA-binding domain is composed of two zinc finger motifs. In the presence of damaged DNA (base pair-excised), the DNA-binding domain will bind the DNA and induce a conformational shift. It has been shown that this binding occurs independent of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cisplatin
Cisplatin is a chemotherapy medication used to treat a number of cancers. These include testicular cancer, ovarian cancer, cervical cancer, breast cancer, bladder cancer, head and neck cancer, esophageal cancer, lung cancer, mesothelioma, brain tumors and neuroblastoma. It is given by injection into a vein. Common side effects include bone marrow suppression, hearing problems, including total irreversible hearing loss, usually restricted to one ear, kidney damage, and vomiting. Other serious side effects include numbness, trouble walking, allergic reactions, electrolyte problems, and heart disease. Use during pregnancy can cause harm to the developing fetus. Cisplatin is in the platinum-based antineoplastic family of medications. It works in part by binding to DNA and inhibiting its replication. Cisplatin was discovered in 1845 and licensed for medical use in 1978 and 1979. It is on the World Health Organization's List of Essential Medicines. Medical use Cisplatin is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NMNAT2
Nicotinamide mononucleotide adenylyltransferase 2 (NMNAT2) is an enzyme that in humans is encoded by the ''NMNAT2'' gene. This gene product belongs to the nicotinamide-nucleotide adenylyltransferase (NMNAT) enzyme family, members of which catalyze an essential step in the nicotinamide adenine dinucleotide (NAD+ (NADP)) biosynthetic pathway. NMNAT2 is cytoplasmic (associated with the Golgi apparatus), and is predominantly expressed in the brain. Two transcript variants encoding different isoforms have been found for this gene. Loss of NMNAT2 initiates Wallerian degeneration. By contrast, NMNAT2 enhancement opposes the actions of SARM1 which would lead to axon degeneration, but this effect is not due to preventing SARM1 depletion of NAD+. Mice lacking NMNAT2 die before birth, but are completely rescued by SARM1 deletion. Activation of NMNAT2 by Sirtuin 3 (SIRT3) may be a means of inhibiting axon degeneration and dysfunction. The catechin epigallocatechin gallate (EGCG) found in te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
