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Equilibrative Nucleoside Transporter
Members of the Equilibrative Nucleoside Transporter (ENT) FamilyTC# 2.A.57 are transport proteins that are specific to nucleosides and nucleobases, and are part of the major facilitator superfamily. They generally possess at least 6, typically 10, transmembrane segments (TMSs) and are 300-600 amino acyl residues in length. Function ENTs, including those in parasitic protozoa, function in nucleoside and nucleobase uptake for salvage pathways of nucleotide synthesis and, in humans, are also responsible for the cellular uptake of nucleoside analogues used in the treatment of cancers and viral diseases. By regulating the concentration of adenosine available to cell surface receptors, mammalian ENTs additionally influence physiological processes ranging from cardiovascular activity to neurotransmission. Human ENTs In humans ENT are also known as SLC29, a group of plasmalemmal transport proteins which transport nucleoside substrates like adenosine into cells. There are four known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleoside
Nucleosides are glycosylamines that can be thought of as nucleotides without a phosphate group. A nucleoside consists simply of a nucleobase (also termed a nitrogenous base) and a five-carbon sugar (ribose or 2'-deoxyribose) whereas a nucleotide is composed of a nucleobase, a five-carbon sugar, and one or more phosphate groups. In a nucleoside, the anomeric carbon is linked through a glycosidic bond to the N9 of a purine or the N1 of a pyrimidine. Nucleotides are the molecular building-blocks of DNA and RNA. List of nucleosides and corresponding nucleobases The reason for 2 symbols, shorter and longer, is that the shorter ones are better for contexts where explicit disambiguation is superfluous (because context disambiguates) and the longer ones are for contexts where explicit disambiguation is judged to be needed or wise. For example, when discussing long nucleobase sequences in genomes, the CATG symbol system is much preferable to the Cyt-Ade-Thy-Gua symbol system (see '' N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equilibrative Nucleoside Transporter 4
The plasma membrane monoamine transporter (PMAT) is a low-affinity monoamine transporter protein which in humans is encoded by the ''SLC29A4'' gene. It is known alternatively as the human equilibrative nucleoside transporter-4 (hENT4). Unlike other members of the ENT family, it is impermeable to most nucleosides, with the exception of the inhibitory neurotransmitter and ribonucleoside adenosine, which it is permeable to in a highly pH-dependent manner. This protein is an integral membrane protein that transports the monoamine neurotransmitters ( serotonin, dopamine, norepinephrine) as well as adenosine, from synaptic spaces into presynaptic neurons or neighboring glial cells. It is abundantly expressed in the human brain, heart tissue, and skeletal muscle, as well as in the kidneys. It is relatively insensitive to the high affinity inhibitors (such as SSRIs) of the SLC6A monoamine transporters (SERT, DAT, NET), as well being only weakly sensitive to the adenosine transport inhi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmembrane Proteins
A transmembrane protein (TP) is a type of integral membrane protein that spans the entirety of the cell membrane. Many transmembrane proteins function as gateways to permit the transport of specific substances across the membrane. They frequently undergo significant conformational changes to move a substance through the membrane. They are usually highly hydrophobic and aggregate and precipitate in water. They require detergents or nonpolar solvents for extraction, although some of them (beta-barrels) can be also extracted using denaturing agents. The peptide sequence that spans the membrane, or the transmembrane segment, is largely hydrophobic and can be visualized using the hydropathy plot. Depending on the number of transmembrane segments, transmembrane proteins can be classified as single-span (or bitopic) or multi-span (polytopic). Some other integral membrane proteins are called monotopic, meaning that they are also permanently attached to the membrane, but do not pass t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Membrane Proteins
Membrane proteins are common proteins that are part of, or interact with, biological membranes. Membrane proteins fall into several broad categories depending on their location. Integral membrane proteins are a permanent part of a cell membrane and can either penetrate the membrane (transmembrane) or associate with one or the other side of a membrane ( integral monotopic). Peripheral membrane proteins are transiently associated with the cell membrane. Membrane proteins are common, and medically important—about a third of all human proteins are membrane proteins, and these are targets for more than half of all drugs. Nonetheless, compared to other classes of proteins, determining membrane protein structures remains a challenge in large part due to the difficulty in establishing experimental conditions that can preserve the correct conformation of the protein in isolation from its native environment. Function Membrane proteins perform a variety of functions vital to the surv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Families
A protein family is a group of evolutionarily related proteins. In many cases, a protein family has a corresponding gene family, in which each gene encodes a corresponding protein with a 1:1 relationship. The term "protein family" should not be confused with family as it is used in taxonomy. Proteins in a family descend from a common ancestor and typically have similar three-dimensional structures, functions, and significant sequence similarity. The most important of these is sequence similarity (usually amino-acid sequence), since it is the strictest indicator of homology and therefore the clearest indicator of common ancestry. A fairly well developed framework exists for evaluating the significance of similarity between a group of sequences using sequence alignment methods. Proteins that do not share a common ancestor are very unlikely to show statistically significant sequence similarity, making sequence alignment a powerful tool for identifying the members of protein familie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleoside Transporter
Nucleoside transporters (NTs) are a group of membrane transport proteins which transport nucleoside substrates like adenosine across the membranes of cells and/or vesicles. There are two known types of nucleoside transporters, concentrative nucleoside transporters (CNTs; SLC28) and equilibrative nucleoside transporter Members of the Equilibrative Nucleoside Transporter (ENT) FamilyTC# 2.A.57 are transport proteins that are specific to nucleosides and nucleobases, and are part of the major facilitator superfamily. They generally possess at least 6, typically 10, ...s (ENTs; SLC29), as well as possibly a yet-unidentified vesicular transporter. References Further reading * * * * Transmembrane transporters {{membrane-protein-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concentrative Nucleoside Transporter
Human concentrative nucleoside transporters include SLC28A1, SLC28A2 and SLC28A3 proteins. SLC28A2 is a purine-specific Na+-nucleoside cotransporter localised to the bile canalicular membrane. SLC28A1 is a Na+-dependent nucleoside transporter selective for pyrimidine nucleosides and adenosine. It also transports the anti-viral nucleoside analogues Zidovudine and Zalcitabine Zalcitabine (2′-3′-di deoxycytidine, ddC), also called dideoxycytidine, is a nucleoside analog reverse-transcriptase inhibitor (NRTI) sold under the trade name Hivid. Zalcitabine was the third antiretroviral to be approved by the Food and Drug .... References {{InterPro content, IPR011657 Protein families Transmembrane transporters ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gemcitabine
Gemcitabine, with brand names including Gemzar, is a chemotherapy medication. It treats cancers including testicular cancer, breast cancer, ovarian cancer, non-small cell lung cancer, pancreatic cancer, and bladder cancer. It is administered by intravenous infusion. It acts against neoplastic growth, and it inhibits the replication of Orthohepevirus A, the causative agent of Hepatitis E, through upregulation of interferon signaling. Common side effects include bone marrow suppression, liver and kidney problems, nausea, fever, rash, shortness of breath, mouth sores, diarrhea, neuropathy, and hair loss. Use during pregnancy will likely result in fetal harm. Gemcitabine is in the nucleoside analog family of medication. It works by blocking the creation of new DNA, which results in cell death. Gemcitabine was patented in 1983 and was approved for medical use in 1995. Generic versions were introduced in Europe in 2009 and in the US in 2010. It is on the WHO Model List of Essentia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equilibrative Nucleoside Transporter 2
Equilibrative nucleoside transporter 2 (ENT2) is a protein that in humans is encoded by the ''SLC29A2'' gene. See also * Solute carrier family * Equilibrative nucleoside transporters * Nucleoside transporter Nucleoside transporters (NTs) are a group of membrane transport proteins which transport nucleoside substrates like adenosine across the membranes of cells and/or vesicles. There are two known types of nucleoside transporters, concentrative nuc ...s References Further reading * * * * * * * * * * * * * * * * Solute carrier family Neurotransmitter transporters {{membrane-protein-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equilibrative Nucleoside Transporter 1
Equilibrative nucleoside transporter 1 (ENT1) is a protein that in humans is encoded by the ''SLC29A1'' gene. Multiple alternatively spliced variants, encoding the same protein, have been found for this gene. Expressed on red blood cell surfaces, these variants make up the Augustine blood group system. Function This gene is a member of the equilibrative nucleoside transporter family. The gene encodes a transmembrane glycoprotein that localizes to the plasma and mitochondrial membranes and mediates the cellular uptake of nucleosides from the surrounding medium. The protein is categorized as an equilibrative (as opposed to concentrative) transporter that is sensitive to inhibition by nitrobenzylmercaptopurine ribonucleoside (NBMPR). Nucleoside transporters are required for nucleotide synthesis in cells that lack ''de novo'' nucleoside synthesis pathways, and are also necessary for the uptake of cytotoxic nucleosides used for cancer and viral chemotherapies. Genomics The gene enc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vasodilation
Vasodilation is the widening of blood vessels. It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. The process is the opposite of vasoconstriction, which is the narrowing of blood vessels. When blood vessels dilate, the flow of blood is increased due to a decrease in vascular resistance and increase in cardiac output. Therefore, dilation of arterial blood vessels (mainly the arterioles) decreases blood pressure. The response may be intrinsic (due to local processes in the surrounding tissue) or extrinsic (due to hormones or the nervous system). In addition, the response may be localized to a specific organ (depending on the metabolic needs of a particular tissue, as during strenuous exercise), or it may be systemic (seen throughout the entire systemic circulation). Endogenous substances and drugs that cause vasodilation are termed vasodilators. Such vasoactivity is necessary for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dilazep
Dilazep is a vasodilator that acts as an adenosine reuptake inhibitor. It is used for the treatment of cardiopathy and renal disorders. Synthesis The reaction of bis-(3-hydroxypropyl)-ethylene diamine (1) with 1-Bromo-3-chloropropane (2) gives homopiperazine 9970-80-0 (3). Esterification by reaction with 3,4,5-Trimethoxybenzoyl Chloride 521-61-3(4) completed the synthesis of Dilazep (5). See also * Hexobendine Hexobendine is a vasodilator that acts as an adenosine reuptake inhibitor An adenosine reuptake inhibitor (AdoRI) is a type of drug which acts as a reuptake inhibitor for the purine nucleoside and neurotransmitter adenosine by blocking the acti ..., a drug with similar chemical structure References Vasodilators Pyrogallol ethers Benzoate esters Diazepanes Adenosine reuptake inhibitors {{cardiovascular-drug-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
