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Inosine
Inosine is a nucleoside that is formed when hypoxanthine is attached to a ribose ring (also known as a ribofuranose) via a β-N9- glycosidic bond. It was discovered in 1965 in analysis of RNA transferase. Inosine is commonly found in tRNAs and is essential for proper translation of the genetic code in wobble base pairs. Knowledge of inosine metabolism has led to advances in immunotherapy in recent decades. Inosine monophosphate is oxidised by the enzyme inosine monophosphate dehydrogenase, yielding xanthosine monophosphate, a key precursor in purine metabolism. Mycophenolate mofetil is an anti-metabolite, anti-proliferative drug that acts as an inhibitor of inosine monophosphate dehydrogenase. It is used in the treatment of a variety of autoimmune diseases including granulomatosis with polyangiitis because the uptake of purine by actively dividing B cells can exceed 8 times that of normal body cells, and, therefore, this set of white cells (which cannot operate purine salva ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inosine Monophosphate Dehydrogenase
Inosine is a nucleoside that is formed when hypoxanthine is attached to a ribose ring (also known as a ribofuranose) via a β-N9-glycosidic bond. It was discovered in 1965 in analysis of RNA transferase. Inosine is commonly found in tRNAs and is essential for proper translation of the genetic code in wobble base pairs. Knowledge of inosine metabolism has led to advances in immunotherapy in recent decades. Inosine monophosphate is oxidised by the enzyme inosine monophosphate dehydrogenase, yielding xanthosine monophosphate, a key precursor in purine metabolism. Mycophenolate mofetil is an anti-metabolite, anti-proliferative drug that acts as an inhibitor of inosine monophosphate dehydrogenase. It is used in the treatment of a variety of autoimmune diseases including granulomatosis with polyangiitis because the uptake of purine by actively dividing B cells can exceed 8 times that of normal body cells, and, therefore, this set of white cells (which cannot operate purine salvage pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Purine Nucleoside Phosphorylase
Purine nucleoside phosphorylase, PNP, PNPase or inosine phosphorylase () is an enzyme that in humans is encoded by the ''NP'' gene. It catalyzes the chemical reaction :purine nucleoside + phosphate \rightleftharpoons purine + alpha-D-ribose 1-phosphate Thus, the two substrates of this enzyme are a purine nucleoside and phosphate, whereas its products are a purine and alpha-D-ribose 1-phosphate. Nomenclature This enzyme belongs to the family of glycosyltransferases, specifically the pentosyltransferases. The systematic name of this enzyme class is purine-nucleoside:phosphate ribosyltransferase. Other names in common use include: * inosine phosphorylase * PNPase * PUNPI * PUNPII * inosine-guanosine phosphorylase * nucleotide phosphatase * purine deoxynucleoside phosphorylase * purine deoxyribonucleoside phosphorylase * purine nucleoside phosphorylase * purine ribonucleoside phosphorylas This enzyme participates in 3 metabolic pathways: purine metabolism, pyrimidine me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mycophenolate Mofetil
Mycophenolic acid (MPA) is an immunosuppressant medication used to prevent rejection following organ transplantation and to treat autoimmune conditions such as Crohn's disease and lupus. Specifically it is used following kidney, heart, and liver transplantation. It can be given by mouth or by injection into a vein. It comes as mycophenolate sodium and mycophenolate mofetil. Common side effects include nausea, infections, and diarrhea. Other serious side effects include an increased risk of cancer, progressive multifocal leukoencephalopathy, anemia, and gastrointestinal bleeding. Use during pregnancy may harm the baby. It works by blocking inosine monophosphate dehydrogenase (IMPDH), which is needed by lymphocytes to make guanosine. Mycophenolic acid was initially discovered by Italian Bartolomeo Gosio in 1893. It was rediscovered in 1945 and 1968. It was approved for medical use in the United States in 1995 following the discovery of its immunosuppressive properties in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wobble Base Pair
A wobble base pair is a pairing between two nucleotides in RNA molecules that does not follow Watson-Crick base pair rules. The four main wobble base pairs are guanine-uracil (G-U), hypoxanthine-uracil (I-U), hypoxanthine-adenine (I-A), and hypoxanthine-cytosine (I-C). In order to maintain consistency of nucleic acid nomenclature, "I" is used for hypoxanthine because hypoxanthine is the nucleobase of inosine; nomenclature otherwise follows the names of nucleobases and their corresponding nucleosides (e.g., "G" for both guanine and guanosine – as well as for deoxyguanosine). The thermodynamic stability of a wobble base pair is comparable to that of a Watson-Crick base pair. Wobble base pairs are fundamental in RNA secondary structure and are critical for the proper translation of the genetic code. Brief history In the genetic code, there are 43 = 64 possible codons (3 nucleotide sequences). For translation, each of these codons requires a tRNA molecule with an anticodon with whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inosine Monophosphate
Inosinic acid or inosine monophosphate (IMP) is a nucleotide (that is, a nucleoside monophosphate). Widely used as a flavor enhancer, it is typically obtained from chicken byproducts or other meat industry waste. Inosinic acid is important in metabolism. It is the ribonucleotide of hypoxanthine and the first nucleotide formed during the synthesis of purine nucleotides. It can also be formed by the deamination of adenosine monophosphate by AMP deaminase. It can be hydrolysed to inosine. The enzyme deoxyribonucleoside triphosphate pyrophosphohydrolase, encoded by YJR069C in ''Saccharomyces cerevisiae'' and containing (d)ITPase and (d)XTPase activities, hydrolyzes inosine triphosphate (ITP) releasing pyrophosphate and IMP. Important derivatives of inosinic acid include the purine nucleotides found in nucleic acids and adenosine triphosphate, which is used to store chemical energy in muscle and other tissues. In the food industry, inosinic acid and its salts such as disodium inosi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TRNA
Transfer RNA (abbreviated tRNA and formerly referred to as sRNA, for soluble RNA) is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length (in eukaryotes), that serves as the physical link between the mRNA and the amino acid sequence of proteins. tRNAs genes from Bacteria are typically shorter (mean = 77.6 bp) than tRNAs from Archaea (mean = 83.1 bp) and eukaryotes (mean = 84.7 bp). The mature tRNA follows an opposite pattern with tRNAs from Bacteria being usually longer (median = 77.6 nt) than tRNAs from Archaea (median = 76.8 nt), with eukaryotes exhibiting the shortest mature tRNAs (median = 74.5 nt). Transfer RNA (tRNA) does this by carrying an amino acid to the protein synthesizing machinery of a cell called the ribosome. Complementation of a 3-nucleotide codon in a messenger RNA (mRNA) by a 3-nucleotide anticodon of the tRNA results in protein synthesis based on the mRNA code. As such, tRNAs are a necessary component of translation, the biologica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Purine
Purine is a heterocyclic aromatic organic compound that consists of two rings ( pyrimidine and imidazole) fused together. It is water-soluble. Purine also gives its name to the wider class of molecules, purines, which include substituted purines and their tautomers. They are the most widely occurring nitrogen-containing heterocycles in nature. Dietary sources Purines are found in high concentration in meat and meat products, especially internal organs such as liver and kidney. In general, plant-based diets are low in purines. High-purine plants and algae include some legumes (lentils and black eye peas) and spirulina. Examples of high-purine sources include: sweetbreads, anchovies, sardines, liver, beef kidneys, brains, meat extracts (e.g., Oxo, Bovril), herring, mackerel, scallops, game meats, yeast ( beer, yeast extract, nutritional yeast) and gravy. A moderate amount of purine is also contained in red meat, beef, pork, poultry, fish and seafood, asparagus, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypoxanthine
Hypoxanthine is a naturally occurring purine derivative. It is occasionally found as a constituent of nucleic acids, where it is present in the anticodon of tRNA in the form of its nucleoside inosine. It has a tautomer known as 6-hydroxypurine. Hypoxanthine is a necessary additive in certain cells, bacteria, and parasite cultures as a substrate and nitrogen source. For example, it is commonly a required reagent in malaria parasite cultures, since ''Plasmodium falciparum'' requires a source of hypoxanthine for nucleic acid synthesis and energy metabolism. In August 2011, a report, based on NASA studies with meteorites found on Earth, was published suggesting hypoxanthine and related organic molecules, including the DNA and RNA components adenine and guanine, may have been formed extraterrestrially in outer space. The '' Pheretima aspergillum'' worm, used in Chinese medicine preparations, contains hypoxanthine. Reactions It is one of the products of the action of xanthine oxidase ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adenine
Adenine () ( symbol A or Ade) is a nucleobase (a purine derivative). It is one of the four nucleobases in the nucleic acid of DNA that are represented by the letters G–C–A–T. The three others are guanine, cytosine and thymine. Its derivatives have a variety of roles in biochemistry including cellular respiration, in the form of both the energy-rich adenosine triphosphate (ATP) and the cofactors nicotinamide adenine dinucleotide (NAD), flavin adenine dinucleotide (FAD) and Coenzyme A. It also has functions in protein synthesis and as a chemical component of DNA and RNA. The shape of adenine is complementary to either thymine in DNA or uracil in RNA. The adjacent image shows pure adenine, as an independent molecule. When connected into DNA, a covalent bond is formed between deoxyribose sugar and the bottom left nitrogen (thereby removing the existing hydrogen atom). The remaining structure is called an ''adenine residue'', as part of a larger molecule. Adenosine is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adenosine
Adenosine (symbol A) is an organic compound that occurs widely in nature in the form of diverse derivatives. The molecule consists of an adenine attached to a ribose via a β-N9- glycosidic bond. Adenosine is one of the four nucleoside building blocks of RNA (and its derivative deoxyadenosine is a building block of DNA), which are essential for all life. Its derivatives include the energy carriers adenosine mono-, di-, and triphosphate, also known as AMP/ADP/ATP. Cyclic adenosine monophosphate (cAMP) is pervasive in signal transduction. Adenosine is used as an intravenous medication for some cardiac arrhythmias. Adenosyl (abbreviated Ado or 5'-dAdo) is the chemical group formed by removal of the 5′-hydroxy (OH) group. It is found in adenosylcobalamin (an active form of vitamin B12) and as a radical in radical SAM enzymes. Medical uses Supraventricular tachycardia In individuals with supraventricular tachycardia (SVT), adenosine is used to help identify and convert t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primer (molecular Biology)
Primer may refer to: Arts, entertainment, and media Films * ''Primer'' (film), a 2004 feature film written and directed by Shane Carruth * ''Primer'' (video), a documentary about the funk band Living Colour Literature * Primer (textbook), a textbook used in primary education to teach the alphabet and other basic subjects * Primer (prayer book), a common name for English prayer books used from the 13th to 16th centuries * '' The New England Primer'' (1688), a Puritan book from Colonial America with morality-themed rhymes Music * ''Primer'' (album), a 1995 music album by the musical group Rockapella * Primer 55, an American alternative metal band * "The Primer", a song from the 2005 album ''Alaska'' by Between the Buried and Me Firearms * Primer (firearms), a firearm powder charge-ignition mechanism ** Centerfire ammunition, Boxer or Berdan primers used in modern centerfire cartridges ** Detonator, a small explosive device also known as an explosive primer or blasting cap * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymerase Chain Reaction
The polymerase chain reaction (PCR) is a method widely used to rapidly make millions to billions of copies (complete or partial) of a specific DNA sample, allowing scientists to take a very small sample of DNA and amplify it (or a part of it) to a large enough amount to study in detail. PCR was invented in 1983 by the American biochemist Kary Mullis at Cetus Corporation; Mullis and biochemist Michael Smith, who had developed other essential ways of manipulating DNA, were jointly awarded the Nobel Prize in Chemistry in 1993. PCR is fundamental to many of the procedures used in genetic testing and research, including analysis of ancient samples of DNA and identification of infectious agents. Using PCR, copies of very small amounts of DNA sequences are exponentially amplified in a series of cycles of temperature changes. PCR is now a common and often indispensable technique used in medical laboratory research for a broad variety of applications including biomedical resear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
