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Enzyme Induction And Inhibition
Enzyme induction is a process in which a molecule (''e.g.'' a drug) induces (''i.e.'' initiates or enhances) the expression of an enzyme. Enzyme inhibition can refer to * the inhibition of the expression of the enzyme by another molecule * interference at the enzyme-level, basically with how the enzyme works. This can be competitive inhibition, uncompetitive inhibition, non-competitive inhibition or partially competitive inhibition. If the molecule induces enzymes that are responsible for its own metabolism, this is called auto-induction (or auto-inhibition if there is inhibition). These processes are particular forms of gene expression regulation. These terms are of particular interest to pharmacology, and more specifically to drug metabolism and drug interactions. They also apply to molecular biology. History In the late 1950s and early 1960s, the French molecular biologists François Jacob and Jacques Monod became the first to explain enzyme induction, in the context of ... [...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 react ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jacques Monod
Jacques Lucien Monod (February 9, 1910 – May 31, 1976) was a French biochemist who won the Nobel Prize in Physiology or Medicine in 1965, sharing it with François Jacob and André Lwoff "for their discoveries concerning genetic control of enzyme and virus synthesis".'' Chance and Necessity: An Essay on the Natural Philosophy of Modern Biology'' by Jacques Monod, New York, Alfred A. Knopf, 1971, Monod and Jacob became famous for their work on the '' E. coli'' ''lac'' operon, which encodes proteins necessary for the transport and breakdown of the sugar lactose (lac). From their own work and the work of others, they came up with a model for how the levels of some proteins in a cell are controlled. In their model, the manufacture of proteins, such as the ones encoded within the ''lac'' (lactose) operon, is prevented when a repressor, encoded by a regulatory gene, binds to its operator, a specific site in the DNA sequence that is close to the genes encoding the proteins. (It i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sensitive Index Substrates
In chemistry, the term substrate is highly context-dependent. Broadly speaking, it can refer either to a chemical species being observed in a chemical reaction, or to a surface on which other chemical reactions or microscopy are performed. In the former sense, a reagent is added to the ''substrate'' to generate a product through a chemical reaction. The term is used in a similar sense in synthetic and organic chemistry, where the substrate is the chemical of interest that is being modified. In biochemistry, an enzyme substrate is the material upon which an enzyme acts. When referring to Le Chatelier's principle, the substrate is the reagent whose concentration is changed. ;Spontaneous reaction : :*Where S is substrate and P is product. ;Catalysed reaction : :*Where S is substrate, P is product and C is catalyst. In the latter sense, it may refer to a surface on which other chemical reactions are performed or play a supporting role in a variety of spectroscopic and microsc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drug Interaction
Drug interactions occur when a drug's mechanism of action is disturbed by the concomitant administration of substances such as foods, beverages, or other drugs. The cause is often the inhibition of the specific receptors available to the drug, forcing the drug molecules to bind to other non-intended targets which results in an array of side-effects. The term selectivity describes a drug’s ability to target a single receptor, rendering a predictable physiological response. For example, the binding of acetylcholine to muscarinic tracheal smooth-muscle receptors (M3) results in smooth muscle contractions. When free receptors become occupied by agonists - drugs that bind and activate receptors - and antagonists - drugs that inhibit/ block activation - the opportunity for drugs to target their intended receptor decreases as most receptors are already occupied. Therefore, when the number of free receptors decreases, the drugs begin binding to other secondary receptors, caus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metabolic Pathway
In biochemistry, a metabolic pathway is a linked series of chemical reactions occurring within a cell. The reactants, products, and intermediates of an enzymatic reaction are known as metabolites, which are modified by a sequence of chemical reactions catalyzed by enzymes. In most cases of a metabolic pathway, the product of one enzyme acts as the substrate for the next. However, side products are considered waste and removed from the cell. These enzymes often require dietary minerals, vitamins, and other cofactors to function. Different metabolic pathways function based on the position within a eukaryotic cell and the significance of the pathway in the given compartment of the cell. For instance, the, electron transport chain, and oxidative phosphorylation all take place in the mitochondrial membrane. In contrast, glycolysis, pentose phosphate pathway, and fatty acid biosynthesis all occur in the cytosol of a cell. There are two types of metabolic pathways that are charact ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aryl Hydrocarbon Receptor
The aryl hydrocarbon receptor (also known as AhR, AHR, ahr, ahR, or dioxin receptor) is a protein that in humans is encoded by the AHR gene. The aryl hydrocarbon receptor is a transcription factor that regulates gene expression. It was originally thought to function primarily as a sensor of xenobiotic chemicals and also as the regulator of enzymes such as cytochrome P450s that metabolize these chemicals. The most notable of these xenobiotic chemicals are aromatic (aryl) hydrocarbons from which the receptor derives its name. More recently, it has been discovered that AhR is activated (or deactivated) by a number of endogenous indole derivatives such as kynurenine. In addition to regulating metabolism enzymes, the AhR has roles in regulating immunity, stem cell maintenance, and cellular differentiation. The aryl hydrocarbon receptor is a member of the family of basic helix-loop-helix transcription factors. AHR binds several exogenous ligands such as natural plant flavonoids, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
André Lwoff
André — sometimes transliterated as Andre — is the French and Portuguese form of the name Andrew, and is now also used in the English-speaking world. It used in France, Quebec, Canada and other French-speaking countries. It is a variation of the Greek name ''Andreas'', a short form of any of various compound names derived from ''andr-'' 'man, warrior'. The name is popular in Norway and Sweden. Cognate names Cognate names are: * Bulgarian: Andrei, Andrey[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nobel Prize In Physiology Or Medicine
The Nobel Prize in Physiology or Medicine is awarded yearly by the Nobel Assembly at the Karolinska Institute for outstanding discoveries in physiology or medicine. The Nobel Prize is not a single prize, but five separate prizes that, according to Alfred Nobel's 1895 will, are awarded "to those who, during the preceding year, have conferred the greatest benefit to humankind". Nobel Prizes are awarded in the fields of Physics, Chemistry, Physiology or Medicine, Literature, and Peace. The Nobel Prize is presented annually on the anniversary of Alfred Nobel's death, 10 December. As of 2022, 114 Nobel Prizes in Physiology or Medicine have been awarded to 226 laureates, 214 men and 12 women. The first one was awarded in 1901 to the German physiologist, Emil von Behring, for his work on serum therapy and the development of a vaccine against diphtheria Diphtheria is an infection caused by the bacterium '' Corynebacterium diphtheriae''. Most infections are asymptomatic or ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthur Pardee
Arthur Beck Pardee (July 13, 1921 – February 24, 2019) was an American biochemist. One biographical portrait begins "Among the titans of science, Arthur Pardee is especially intriguing." There is hardly a field of molecular biology that is not affected by his work, which has advanced our understanding through theoretical predictions followed by insightful experiments. He is perhaps most famous for his part in the 'PaJaMo experiment' of the late 1950s, which greatly helped in the discovery of messenger RNA. He is also well known as the discoverer of the restriction point, in which a cell commits itself to certain cell cycle events during the G1 cycle. He did a great deal of work on tumor growth and regulation, with a particular focus on the role of estrogen in hormone-responsive tumors. He is also well known for the development of various biochemical research techniques, most notably the differential display methodology, which is used in examining the activation of genes in cell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joshua Lederberg
Joshua () or Yehoshua ( ''Yəhōšuaʿ'', Tiberian: ''Yŏhōšuaʿ,'' lit. 'Yahweh is salvation') ''Yēšūaʿ''; syr, ܝܫܘܥ ܒܪ ܢܘܢ ''Yəšūʿ bar Nōn''; el, Ἰησοῦς, ar , يُوشَعُ ٱبْنُ نُونٍ '' Yūšaʿ ibn Nūn''; la, Iosue functioned as Moses' assistant in the books of Exodus and Numbers, and later succeeded Moses as leader of the Israelite tribes in the Hebrew Bible's Book of Joshua. His name was Hoshea ( ''Hōšēaʿ'', lit. 'Save') the son of Nun, of the tribe of Ephraim, but Moses called him "Yehoshua" (translated as "Joshua" in English),''Bible'' the name by which he is commonly known in English. According to the Bible, he was born in Egypt prior to the Exodus. The Hebrew Bible identifies Joshua as one of the twelve spies of Israel sent by Moses to explore the land of Canaan. In Numbers 13:1, and after the death of Moses, he led the Israelite tribes in the conquest of Canaan, and allocated lands to the tribes. According to bi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lac Repressor
The ''lac'' repressor (LacI) is a DNA-binding protein that inhibits the expression of genes coding for proteins involved in the metabolism of lactose in bacteria. These genes are repressed when lactose is not available to the cell, ensuring that the bacterium only invests energy in the production of machinery necessary for uptake and utilization of lactose when lactose is present. When lactose becomes available, it is firstly converted into allolactose by β-Galactosidase ( lacZ) in bacteria. The DNA binding ability of lac repressor bound with allolactose is inhibited due to allosteric regulation, thereby genes coding for proteins involved in lactose uptake and utilization can be expressed. Function The ''lac'' repressor (LacI) operates by a helix-turn-helix motif in its DNA-binding domain, binding base-specifically to the major groove of the operator region of the ''lac'' operon, with base contacts also made by residues of symmetry-related alpha helices, the "hinge" helic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
