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Lingual Lipase
Lingual lipase is a member of a family of digestive enzymes called triacylglycerol lipases, EC 3.1.1.3, that use the catalytic triad of aspartate, histidine, and serine to hydrolyze medium and long-chain triglycerides into partial glycerides and free fatty acids. The enzyme, released into the mouth along with the saliva, catalyzes the first reaction in the digestion of dietary lipid, with diglycerides being the primary reaction product. However, due to the unique characteristics of lingual lipase, including a pH optimum 4.5–5.4 and its ability to catalyze reactions without bile salts, the lipolytic activity continues through to the stomach. Enzyme release is signaled by autonomic nervous system after ingestion, at which time the serous glands under the circumvallate and foliate lingual papillae on the surface of the tongue secrete lingual lipase to the grooves of the circumvallate and foliate papillae, co-localized with fat taste receptors. The hydrolysis of the dietary fats is ... [...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] |
Enzyme Replacement Therapy
Enzyme replacement therapy (ERT) is a medical treatment which replaces an enzyme that is deficient or absent in the body. Usually, this is done by giving the patient an intravenous (IV) infusion of a solution containing the enzyme. ERT is available for some lysosomal storage diseases: Gaucher disease, Fabry disease, MPS I, MPS II (Hunter syndrome), MPS VI and Pompe disease. ERT does not correct the underlying genetic defect, but it increases the concentration of the enzyme that the patient is lacking. ERT has also been used to treat patients with severe combined immunodeficiency (SCID) resulting from an adenosine deaminase deficiency (ADA-SCID). Other treatment options for patients with enzyme or protein deficiencies include substrate reduction therapy, gene therapy, and bone-marrow derived stem cell transplantation. History ERT was developed in 1964 by Christian de Duve and Roscoe Brady. Leading work was done on this subject at the Department of Physiology at the Univers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duodenum
The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear, and the terms anterior intestine or proximal intestine may be used instead of duodenum. In mammals the duodenum may be the principal site for iron absorption. The duodenum precedes the jejunum and ileum and is the shortest part of the small intestine. In humans, the duodenum is a hollow jointed tube about 25–38 cm (10–15 inches) long connecting the stomach to the middle part of the small intestine. It begins with the duodenal bulb and ends at the suspensory muscle of duodenum. Duodenum can be divided into four parts: the first (superior), the second (descending), the third (horizontal) and the fourth (ascending) parts. Structure The duodenum is a C-shaped structure lying adjacent to the stomach. It is divided anatomically into four sections. The first part of the duodenum lies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pancreatic Lipase
Triglyceride lipases () are a family of lipolytic enzymes that hydrolyse ester linkages of triglycerides. Lipases are widely distributed in animals, plants and prokaryotes. At least three tissue-specific isozymes exist in higher vertebrates, pancreatic, hepatic and gastric/lingual. These lipases are closely related to each other and to lipoprotein lipase (), which hydrolyses triglycerides of chylomicrons and very low density lipoproteins (VLDL). The most conserved region in all these proteins is centred on a serine residue which has been shown to participate, with a histidine and an aspartic acid residue, in a charge relay system. Such a region is also present in lipases of prokaryotic origin and in lecithin-cholesterol acyltransferase () (LCAT), which catalyzes fatty acid transfer between phosphatidylcholine and cholesterol. Human pancreatic lipase ''Pancreatic lipase'', also known as ''pancreatic triacylglycerol lipase'' or ''steapsin'', is an enzyme secreted from the pancre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exocrine Pancreatic Insufficiency
Exocrine pancreatic insufficiency (EPI) is the inability to properly digest food due to a lack of digestive enzymes made by the pancreas. EPI is found in humans afflicted with cystic fibrosis and Shwachman–Diamond syndrome, and is common in dogs. EPI is caused by a progressive loss of the pancreatic cells that make digestive enzymes; loss of digestive enzymes leads to maldigestion and malabsorption of nutrients from normal digestive processes. Chronic pancreatitis is the most common cause of EPI in humans and cats. In dogs, the most common cause is ''pancreatic acinar atrophy'', arising as a result of genetic conditions, a blocked pancreatic duct, or prior infection. The exocrine pancreas is a portion of this organ that contains clusters of ducts (acini) producing bicarbonate anion, a mild alkali, as well as an array of digestive enzymes that together empty by way of the interlobular and main pancreatic ducts into the duodenum (upper small intestine). The hormones cholecy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cystic Fibrosis
Cystic fibrosis (CF) is a rare genetic disorder that affects mostly the lungs, but also the pancreas, liver, kidneys, and intestine. Long-term issues include difficulty breathing and coughing up mucus as a result of frequent lung infections. Other signs and symptoms may include sinus infections, poor growth, fatty stool, clubbing of the fingers and toes, and infertility in most males. Different people may have different degrees of symptoms. Cystic fibrosis is inherited in an autosomal recessive manner. It is caused by the presence of mutations in both copies of the gene for the cystic fibrosis transmembrane conductance regulator (CFTR) protein. Those with a single working copy are carriers and otherwise mostly healthy. CFTR is involved in the production of sweat, digestive fluids, and mucus. When the CFTR is not functional, secretions which are usually thin instead become thick. The condition is diagnosed by a sweat test and genetic testing. Screening of infants at bi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mech2
In science fiction, or mechs are giant robots or machines controlled by people, typically depicted as humanoid walking vehicles. The term was first used in Japanese after shortening the English loanword or , but the meaning in Japanese is more inclusive, and or 'giant robot' is the narrower term. Fictional mecha vary greatly in size and shape, but are distinguished from vehicles by their humanoid or biomorphic appearance, although they are bigger, often much bigger, than human beings. Different subgenres exist, with varying connotations of realism. The concept of Super Robot and Real Robot are two such examples found in Japanese anime and manga. Real-world piloted humanoid or non-humanoid robotic platforms, existing or planned, may also be called "mecha". In Japanese, "mecha" may refer to mobile machinery or vehicles (including aircraft) in general, manned or otherwise. Characteristics 'Mecha' is an abbreviation, first used in Japanese, of 'mechanical'. In Japanese, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monoacylglyceride
Monoglycerides (also: acylglycerols or monoacylglycerols) are a class of glycerides which are composed of a molecule of glycerol linked to a fatty acid via an ester bond. As glycerol contains both primary and secondary alcohol groups two different types of monoglycerides may be formed; 1-monoacylglycerols where the fatty acid is attached to a primary alcohol, or a 2-monoacylglycerols where the fatty acid is attached to the secondary alcohol. Synthesis Monoglycerides are produced both biologically and industrially. They are naturally present at very low levels (0.1-0.2%) in some seed oils such as olive oil, rapeseed oil and cottonseed oil. They are biosynthesized by the enzymatic hydrolysis of triglycerides by lipoprotein lipase and the enzymatic hydrolysis of diglycerides by diacylglycerol lipase; or as an intermediate in the alkanoylation of glycerol to form fats. Several monoglycerides are pharmacologically active (e.g. 2-oleoylglycerol, 2-arachidonoylglycerol). Industrial p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triacylglycerol
A triglyceride (TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids (from ''tri-'' and ''glyceride''). Triglycerides are the main constituents of body fat in humans and other vertebrates, as well as vegetable fat. They are also present in the blood to enable the bidirectional transference of adipose fat and blood glucose from the liver, and are a major component of human skin oils. Many types of triglycerides exist. One specific classification focuses on saturated and unsaturated types. Saturated fats have ''no'' C=C groups; unsaturated fats feature one or more C=C groups. Unsaturated fats tend to have a lower melting point than saturated analogues; as a result, they are often liquid at room temperature. Chemical structure Triglycerides are tri-esters consisting of a glycerol bound to three fatty acid molecules. Alcohols have a hydroxyl (HO–) group. Organic acids have a carboxyl (–COOH) group. Alcohols and organic ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbonyl
In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double-bonded to an oxygen atom: C=O. It is common to several classes of organic compounds, as part of many larger functional groups. A compound containing a carbonyl group is often referred to as a carbonyl compound. The term carbonyl can also refer to carbon monoxide as a ligand in an inorganic or organometallic complex (a metal carbonyl, e.g. nickel carbonyl). The remainder of this article concerns itself with the organic chemistry definition of carbonyl, where carbon and oxygen share a double bond. Carbonyl compounds In organic chemistry, a carbonyl group characterizes the following types of compounds: Other organic carbonyls are urea and the carbamates, the derivatives of acyl chlorides chloroformates and phosgene, carbonate esters, thioesters, lactones, lactams, hydroxamates, and isocyanates. Examples of inorganic carbonyl compounds are carbon dioxide and carbonyl sulfide. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleophilic Addition
In organic chemistry, a nucleophilic addition reaction is an addition reaction where a chemical compound with an electrophilic double or triple bond reacts with a nucleophile, such that the double or triple bond is broken. Nucleophilic additions differ from electrophilic additions in that the former reactions involve the group to which atoms are added accepting electron pairs, whereas the latter reactions involve the group donating electron pairs. Addition to carbon–heteroatom double bonds Nucleophilic addition reactions of nucleophiles with electrophilic double or triple bond (π bonds) create a new carbon center with two additional single, or σ, bonds.March Jerry; (1985). Advanced Organic Chemistry reactions, mechanisms and structure (3rd ed.). New York: John Wiley & Sons, inc. Addition of a nucleophile to carbon–heteroatom double or triple bonds such as >C=O or -C≡N show great variety. These types of bonds are polar (have a large difference in electronegativity betwe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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