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Obestatin
Obestatin is a hormone that is produced in specialized epithelial cells of the stomach and small intestine of several animals including humans. Obestatin was originally identified as an anorectic peptide, but its effect on food intake remains controversial. Discovery Obestatin was discovered using a bioinformatics approach: by computer search of the sequenced genomes of several organisms. * Structure The obestatin structure to the right was determined by NMR. The length of the polypeptide was found to be 24 residues with a secondary structure 29% helical. Specifically 2 helices and 7 residues are formed. Gene and transcription Obestatin is encoded by the same gene that encodes ghrelin, a peptide hormone. The mRNA produced from the ''GHRL'' gene has four exons. Five products of similar structure and function arise: the first is the 117-amino acid ''preproghrelin''. (It is homologous to promotilin; both are members of the motilin family). It is cleaved to produce ''proghrelin'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ghrelin
Ghrelin (; or lenomorelin, INN) is a hormone produced by enteroendocrine cells of the gastrointestinal tract, especially the stomach, and is often called a "hunger hormone" because it increases the drive to eat. Blood levels of ghrelin are highest before meals when hungry, returning to lower levels after mealtimes. Ghrelin may help prepare for food intake by increasing gastric motility and stimulating the secretion of gastric acid. Ghrelin activates cells in the anterior pituitary gland and hypothalamic arcuate nucleus, including neuropeptide Y neurons that initiate appetite. Ghrelin stimulates brain structures having a specific receptor – the growth hormone secretagogue receptor 1A (GHSR-1A). Ghrelin also participates in regulation of reward cognition, learning and memory, the sleep-wake cycle, taste sensation, reward behavior, and glucose metabolism. History and name Ghrelin was discovered after the ghrelin receptor (called growth hormone secretagogue type 1A receptor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ghrelin
Ghrelin (; or lenomorelin, INN) is a hormone produced by enteroendocrine cells of the gastrointestinal tract, especially the stomach, and is often called a "hunger hormone" because it increases the drive to eat. Blood levels of ghrelin are highest before meals when hungry, returning to lower levels after mealtimes. Ghrelin may help prepare for food intake by increasing gastric motility and stimulating the secretion of gastric acid. Ghrelin activates cells in the anterior pituitary gland and hypothalamic arcuate nucleus, including neuropeptide Y neurons that initiate appetite. Ghrelin stimulates brain structures having a specific receptor – the growth hormone secretagogue receptor 1A (GHSR-1A). Ghrelin also participates in regulation of reward cognition, learning and memory, the sleep-wake cycle, taste sensation, reward behavior, and glucose metabolism. History and name Ghrelin was discovered after the ghrelin receptor (called growth hormone secretagogue type 1A receptor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GPR39
G-protein coupled receptor 39 is a protein that in humans is encoded by the ''GPR39'' gene. References Further reading * * * * * * * * * * * * G protein-coupled receptors {{transmembranereceptor-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nesfatin-1
Nesfatin-1 is a neuropeptide produced in the hypothalamus of mammals. It participates in the regulation of hunger and fat storage. Increased nesfatin-1 in the hypothalamus contributes to diminished hunger, a 'sense of fullness', and a potential loss of body fat and weight. A study of metabolic effects of nesfatin-1 in rats have been done in which subjects administered nesfatin-1 ate less, used more stored fat and became more active. Nesfatin-1-induced inhibition of feeding may be mediated through the inhibition of orexigenic neurons. In addition, the protein stimulated insulin secretion from the pancreatic beta cells of both rats and mice. Biochemistry Nesfatin-1 is a polypeptide encoded in the N-terminal region of the protein precursor, Nucleobindin2 (NUCB2). Recombinant human Nesfatin-1 is a 9.7 kDa protein containing 82 amino acid residues. Nesfatin-1 is expressed in the hypothalamus, in other areas of the brain, and in pancreatic islets, gastric endocrine cells and adip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Nuclear Magnetic Resonance Spectroscopy
Nuclear magnetic resonance spectroscopy of proteins (usually abbreviated protein NMR) is a field of structural biology in which NMR spectroscopy is used to obtain information about the structure and dynamics of proteins, and also nucleic acids, and their complexes. The field was pioneered by Richard R. Ernst and Kurt Wüthrich at the ETH, and by Ad Bax, Marius Clore, Angela Gronenborn at the NIH, and Gerhard Wagner at Harvard University, among others. Structure determination by NMR spectroscopy usually consists of several phases, each using a separate set of highly specialized techniques. The sample is prepared, measurements are made, interpretive approaches are applied, and a structure is calculated and validated. NMR involves the quantum-mechanical properties of the central core ("nucleus") of the atom. These properties depend on the local molecular environment, and their measurement provides a map of how the atoms are linked chemically, how close they are in space, and how rapid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Lauryl Sulfate
Sodium dodecyl sulfate (SDS) or sodium lauryl sulfate (SLS), sometimes written sodium laurilsulfate, is an organic compound with the formula . It is an anionic surfactant used in many cleaning and hygiene products. This compound is the sodium salt of the 12-carbon an organosulfate. Its hydrocarbon tail combined with a polar " headgroup" give the compound amphiphilic properties that make it useful as a detergent. SDS is also component of mixtures produced from inexpensive coconut and palm oils. SDS is a common component of many domestic cleaning, personal hygiene and cosmetic, pharmaceutical, and food products, as well as of industrial and commercial cleaning and product formulations. Physicochemical properties The critical micelle concentration (CMC) in water at 25 °C is 8.2 mM, and the aggregation number at this concentration is usually considered to be about 62. The micelle ionization fraction (α) is around 0.3 (or 30%). Applications Cleaning and hygiene SDS is mainly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micelle
A micelle () or micella () (plural micelles or micellae, respectively) is an aggregate (or supramolecular assembly) of surfactant amphipathic lipid molecules dispersed in a liquid, forming a colloidal suspension (also known as associated colloidal system). A typical micelle in water forms an aggregate with the hydrophilic "head" regions in contact with surrounding solvent, sequestering the hydrophobic single-tail regions in the micelle centre. This phase is caused by the packing behavior of single-tail lipids in a bilayer. The difficulty filling all the volume of the interior of a bilayer, while accommodating the area per head group forced on the molecule by the hydration of the lipid head group, leads to the formation of the micelle. This type of micelle is known as a normal-phase micelle (oil-in-water micelle). Inverse micelles have the head groups at the centre with the tails extending out (water-in-oil micelle). Micelles are approximately spherical in shape. Other phases ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anorectic
An anorectic or anorexic is a drug which reduces appetite, resulting in lower food consumption, leading to weight loss. By contrast, an appetite stimulant is referred to as orexigenic. The term is (from the Greek ''ἀν-'' (an-) = "without" and ''ὄρεξις'' (órexis) = "appetite"), and such drugs are also known as anorexigenic, anorexiant, or appetite suppressant. History Used on a short-term basis clinically to treat obesity, some appetite suppressants are also available over-the-counter. Most common natural appetite suppressants are based on ''Hoodia'', a genus of 13 species in the flowering plant family Apocynaceae, under the subfamily Asclepiadoideae. Several appetite suppressants are based on a mix of natural ingredients, mostly using green tea as its basis, in combination with other plant extracts such as fucoxanthin, found naturally in seaweed. Drugs of this class are frequently stimulants of the phenethylamine family, related to amphetamine. The German and Fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bioinformatics
Bioinformatics () is an interdisciplinary field that develops methods and software tools for understanding biological data, in particular when the data sets are large and complex. As an interdisciplinary field of science, bioinformatics combines biology, chemistry, physics, computer science, information engineering, mathematics and statistics to analyze and interpret the biological data. Bioinformatics has been used for '' in silico'' analyses of biological queries using computational and statistical techniques. Bioinformatics includes biological studies that use computer programming as part of their methodology, as well as specific analysis "pipelines" that are repeatedly used, particularly in the field of genomics. Common uses of bioinformatics include the identification of candidates genes and single nucleotide polymorphisms (SNPs). Often, such identification is made with the aim to better understand the genetic basis of disease, unique adaptations, desirable properties (e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motilin
Motilin is a 22-amino acid polypeptide hormone in the motilin family that, in humans, is encoded by the ''MLN'' gene. Motilin is secreted by endocrine Mo cells (also referred to as M cells, which are not the same as the M cells, or microfold cells, found in Peyer's patches) that are numerous in crypts of the small intestine, especially in the duodenum and jejunum. It is released into the general circulation in humans at about 100-min intervals during the inter-digestive state and is the most important factor in controlling the inter-digestive migrating contractions; and it also stimulates endogenous release of the endocrine pancreas. Based on amino acid sequence, motilin is unrelated to other hormones. Because of its ability to stimulate gastric activity, it was named "motilin". Apart from in humans, the motilin receptor has been identified in the gastrointestinal tracts of pigs, rats, cows, and cats, and in the central nervous system of rabbits. Discovery Motilin was discover ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prader–Willi Syndrome
Prader–Willi syndrome (PWS) is a genetic disorder caused by a loss of function of specific genes on chromosome 15. In newborns, symptoms include weak muscles, poor feeding, and slow development. Beginning in childhood, those affected become constantly hungry, which often leads to obesity and type 2 diabetes. Mild to moderate intellectual impairment and behavioral problems are also typical of the disorder. Often, affected individuals have a narrow forehead, small hands and feet, short height, and light skin and hair. Most are unable to have children. About 74% of cases occur when part of the father's chromosome 15 is deleted. In another 25% of cases, the affected person has two copies of the maternal chromosome 15 from the mother and lacks the paternal copy. As parts of the chromosome from the mother are turned off through imprinting, they end up with no working copies of certain genes. PWS is not generally inherited, but rather the genetic changes happen during the format ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
