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Pepsin Inhibitor
Pepsin is an endopeptidase that breaks down proteins into smaller peptides and amino acids. It is one of the main digestive enzymes in the Digestion#Digestive system, digestive systems of humans and many other animals, where it helps digestion, digest the proteins in food. Pepsin is an aspartic protease, using a catalytic aspartate in its active site. It is one of three principal endopeptidases (enzymes cutting proteins in the middle) in the human digestive system, the other two being chymotrypsin and trypsin. There are also exopeptidases which remove individual amino acids at both ends of proteins (carboxypeptidases produced by the pancreas and aminopeptidases secreted by the small intestine). During the process of digestion, these enzymes, each of which is specialized in severing links between particular types of amino acids, collaborate to break down dietary proteins into their components, i.e., peptides and amino acids, which can be readily small intestine#Absorption, abs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pepstatin
Pepstatin is a potent inhibitor of aspartyl proteases. It is a hexa-peptide containing the unusual amino acid statine (Sta, (3S,4S)-4-amino-3-hydroxy-6-methylheptanoic acid), having the sequence Isovaleryl-Val-Val-Sta-Ala-Sta (Iva-Val-Val-Sta-Ala-Sta). It was originally isolated from cultures of various species of Actinomyces due to its ability to inhibit pepsin at picomolar concentrations. It was later found to inhibit nearly all acid proteases with high potency and, as such, has become a valuable research tool, as well as a common constituent of protease inhibitor cocktails. Pepstatin A is well known to be an inhibitor of aspartic proteases such as pepsin, cathepsins D and E. Except for its role as a protease inhibitor, however, the pharmacological action of pepstatin A upon cells remain unclear. Pepstatin A suppresses receptor activator of NF-κB ligand (RANKL)–induced osteoclast differentiation. Pepstatin A suppresses the formation of multinuclear osteoclasts dose-dependen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Small Intestine
The small intestine or small bowel is an organ (anatomy), organ in the human gastrointestinal tract, gastrointestinal tract where most of the #Absorption, absorption of nutrients from food takes place. It lies between the stomach and large intestine, and receives bile and pancreatic juice through the pancreatic duct to aid in digestion. The small intestine is about long and folds many times to fit in the abdomen. Although it is longer than the large intestine, it is called the small intestine because it is narrower in diameter. The small intestine has three distinct regions – the duodenum, jejunum, and ileum. The duodenum, the shortest, is where preparation for absorption through small finger-like protrusions called intestinal villus, intestinal villi begins. The jejunum is specialized for the absorption through its lining by enterocytes: small nutrient particles which have been previously digested by enzymes in the duodenum. The main function of the ileum is to absorb vitami ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Crystallization
Protein crystallization is the process of formation of a regular array of individual protein molecules stabilized by crystal contacts. If the crystal is sufficiently ordered, it will diffract. Some proteins naturally form crystalline arrays, like aquaporin in the lens of the eye. In the process of protein crystallization, proteins are dissolved in an aqueous environment and sample solution until they reach the supersaturated state. Different methods are used to reach that state such as vapor diffusion, microbatch, microdialysis, and free-interface diffusion. Developing protein crystals is a difficult process influenced by many factors, including pH, temperature, ionic strength in the crystallization solution, and even gravity. Once formed, these crystals can be used in structural biology to study the molecular structure of the protein, particularly for various industrial or medical purposes. Development For over 150 years, scientists from all around the world have known a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Online Etymology Dictionary
Etymonline, or ''Online Etymology Dictionary'', sometimes abbreviated as OED (not to be confused with the ''Oxford English Dictionary'', which the site often cites), is a free online dictionary that describes the etymology, origins of English language, English words, written and compiled by Douglas R. Harper. Description Douglas R. Harper is an American Civil War historian and copy editor for LNP Media Group. He compiled the etymology dictionary to record the history and evolution of more than 50,000 words, including slang and technical terms. The core of its etymology information stems from ''The Barnhart Dictionary of Etymology'' by Robert Barnhart, Ernest Klein's ''Comprehensive Etymology Dictionary of the English Language'', ''The Middle English Compendium'', ''The Oxford English Dictionary'', and the 1889–1902 ''Century Dictionary''. Harper also researches on digital archives. On the ''Etymonline'' homepage, Harper says that he considers himself "essentially and for the m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancient Greek
Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek Dark Ages, Dark Ages (), the Archaic Greece, Archaic or Homeric Greek, Homeric period (), and the Classical Greece, Classical period (). Ancient Greek was the language of Homer and of fifth-century Athens, fifth-century Athenian historians, playwrights, and Ancient Greek philosophy, philosophers. It has contributed many words to English vocabulary and has been a standard subject of study in educational institutions of the Western world since the Renaissance. This article primarily contains information about the Homeric Greek, Epic and Classical periods of the language, which are the best-attested periods and considered most typical of Ancient Greek. From the Hellenistic period (), Ancient Greek was followed by Koine Greek, which is regar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theodor Schwann
Theodor Schwann (; 7 December 181011 January 1882) was a German physician and physiology, physiologist. His most significant contribution to biology is considered to be the extension of cell theory to animals. Other contributions include the discovery of Schwann cells in the peripheral nervous system, the discovery and study of pepsin, the discovery of the Organism, organic nature of yeast, and the invention of the term "metabolism". Early life and education Theodor Schwann was born in Neuss on 7 December 1810 to Leonard Schwann and Elisabeth Rottels. Leonard Schwann was a goldsmith and later a printer. Theodor Schwann studied at the Dreikönigsgymnasium (also known as the Tricoronatum or Three Kings School), a Jesuit school in Cologne. Schwann was a devout Roman Catholic. In Cologne his religious instructor , a priest and novelist, emphasized the individuality of the human soul and the importance of free will. In 1829, Schwann enrolled at the University of Bonn in the preme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Swiss Institute Of Bioinformatics
The SIB Swiss Institute of Bioinformatics is an academic not-for-profit foundation which federates bioinformatics activities throughout Switzerland. The institute was established on 30 March 1998 and its mission is to provide core bioinformatics resources to the national and international life science research community in fields such as genomics, proteomics and systems biology as well as to lead and coordinate the field of bioinformatics in Switzerland. In particular, it promotes research, develops databanks and computer technologies, and is involved in teaching and service activities. History The institute was originally created to provide a framework for stable long-term funding for both the Swiss-Prot database and the Swiss EMBnet node. Swiss-Prot in particular went through a major funding crisis in 1996, which led the leaders of the five research groups active in bioinformatics in Geneva and Lausanne, Ron Appel, Amos Bairoch, Philipp Bucher, Victor Jongeneel and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastric Acid
Gastric acid or stomach acid is the acidic component – hydrochloric acid – of gastric juice, produced by parietal cells in the gastric glands of the stomach lining. In humans, the pH is between one and three, much lower than most other animals, but is very similar to that of carrion-eating carnivores that need protection from ingesting pathogens. With this higher acidity, gastric acid plays a key protective role against pathogens. It is also key in the digestion of proteins by activating digestive enzymes, which together break down the long chains of amino acids. Gastric acid is regulated in feedback systems to increase production when needed, such as after a meal. Other cells in the stomach produce bicarbonate, a base, to buffer the fluid, ensuring a regulated pH. These cells also produce mucus – a viscous barrier to prevent gastric acid from damaging the stomach. The pancreas further produces large amounts of bicarbonate, secreting this through the pancreatic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrochloric Acid
Hydrochloric acid, also known as muriatic acid or spirits of salt, is an aqueous solution of hydrogen chloride (HCl). It is a colorless solution with a distinctive pungency, pungent smell. It is classified as a acid strength, strong acid. It is a component of the gastric acid in the digestive systems of most animal species, including humans. Hydrochloric acid is an important laboratory reagent and industrial chemical. Etymology Because it was produced from halite, rock salt according to the methods of Johann Rudolph Glauber, hydrochloric acid was historically called by European alchemists ''spirits of salt'' or ''acidum salis'' (salt acid). Both names are still used, especially in other languages, such as , , , , , , , , , , (''ensan''), zh, 盐酸 (''yánsuān''), and (''yeomsan''). Gaseous HCl was called ''marine acid air''. The name ''muriatic acid'' has the same origin (''muriatic'' means "pertaining to brine or salt", hence ''muriate'' means hydrochloride), and this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastric Chief Cell
A gastric chief cell, peptic cell, or gastric zymogenic cell is a type of gastric gland cell that releases pepsinogen and gastric lipase. It is the cell responsible for secretion of chymosin (rennin) in ruminant animals and some other animals. The cell stains basophilic upon H&E staining due to the large proportion of rough endoplasmic reticulum in its cytoplasm. Gastric chief cells are generally located deep in the mucosal layer of the stomach lining, in the fundus and body of the stomach. Chief cells release the zymogen (enzyme precursor) pepsinogen when stimulated by a variety of factors including cholinergic activity from the vagus nerve and acidic condition in the stomach. Gastrin and secretin may also act as secretagogues. It works in conjunction with the parietal cell, which releases gastric acid, converting the pepsinogen into pepsin. Nomenclature The terms ''chief cell'' and '' zymogenic cell'' are often used without the word "gastric" to name this type of cell. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zymogen
In biochemistry, a zymogen (), also called a proenzyme (), is an inactive precursor of an enzyme. A zymogen requires a biochemical change (such as a hydrolysis reaction revealing the active site, or changing the configuration to reveal the active site) to become an active enzyme. The biochemical change usually occurs in Golgi bodies, where a specific part of the precursor enzyme is cleaved in order to activate it. The inactivating piece which is cleaved off can be a peptide unit, or can be independently-folding domains comprising more than 100 residues. Although they limit the enzyme's ability, these N-terminal extensions of the enzyme or a "prosegment" often aid in the stabilization and folding of the enzyme they inhibit. The pancreas secretes zymogens partly to prevent the enzymes from digesting proteins in the cells where they are synthesised. Enzymes like pepsin are created in the form of pepsinogen, an inactive zymogen. Pepsinogen is activated when chief cells release ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
