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Topic: Allosteric regulation

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KUMC Aron Fenton, PhD At the single protein level, allosteric regulation is the altered functions that result when a regulatory molecule binds to a protein at a site distinct from the protein’ s active site. Instead of limiting our thoughts to a limited number of assumed confirmations, we consider allosteric regulation using thermodynamic arguments that are free of presumed conformational states. This approach also offers the theory for quantifying a "magnitude" of how much allosteric regulation is present instead of treating this regulation as on-or-off; plus-or-minus; all-or-none. www.kumc.edu /biochemistry/Fenton.html   (496 words)

A to H Allosteric regulation is the regulation of the activity of allosteric enzymes. An allosteric enzyme is an enzyme that contains a region to which small, regulatory molecules ("effectors") may bind in addition to and separate from the substrate binding site and thereby affect the catalytic activity. Allosteric binding sites are contained in many enzymes and receptors. www.chem.qmul.ac.uk /iupac/medchem/ah.html   (2005 words)

Ligand Binding Problems (Single site, non-cooperative) Allosteric effects are important in the regulation of enzymatic reactions. Allosteric effects occur when the binding properties of a macromolecule change as a consequence of a second ligand binding to the macromolecule and altering its affinity towards the first, or primary, ligand. The allosteric effector stabilizes the tense state, or lowers its energy relative to that of the relaxed state. stingray.bio.cmu.edu /~web/bc/Lec/Lec13/lec13.html   (695 words)

Enzyme Regulation Allosteric regulation is achieved through noncovalent interactions (binding) of substrates and effectors to the enzyme. Allosteric regulation: regulation of enzyme activity through the binding of allosteric effectors that either activate (positive effectors) or inhibit (negative effectors) the activity of the enzyme: Enzymes subject to such regulation are called allosteric enzymes. www.people.virginia.edu /~rjh9u/IntroBio/bio201/lectures/Lecture14.html   (456 words)

Allosteric Regulation of Catalytic Activity: Escherichia coli Aspartate Transcarbamoylase versus Yeast Chorismate Mutase -- Helmstaedt et al. 65 (3): 404 -- Microbiology and Molecular Biology Reviews Carbamyl phosphate: an allosteric substrate for aspartate transcarbamylase of Escherichia coli. The residues which change their position during allosteric transition and thereby transduce the signal of effector binding from the allosteric to the active site are shown as stick models (green, carbon; blue, nitrogen; red, oxygen). The pAR5 mutation and the allosteric mechanism of Escherichia coli aspartate carbamoyltransferase. mmbr.asm.org /cgi/content/full/65/3/404   (10351 words)

Jean Pierre Changeux and Molecular Neurobiology, History Short-term regulation of acetylcholine receptor efficacy by allosteric effectors : phosphorylation, Ca++ ions and ivermectin (1979-1998) Allosteric transitions of the acetylcholine receptor: the molecular mechanism of desensitization (1972-1983) The initial theory on allosteric proteins, as formulated in 1963, was designed for regulatory enzymes but included references to gene repressors and to hormone receptors. www.pasteur.fr /recherche/unites/neubiomol/history.html   (8987 words)

Are the Common Allosteric Models Correct? For our purposes, allosteric refers to the regulation (either inhibition or activation) of enzyme activity due to the binding of a metabolite to a site on the enzyme that is different from the active site. An allosteric inhibitor binds to an allosteric site and shifts the conformational equilibrium to one that is relatively inactive. The purpose of the experiment is to determine if the individual allosteric sites (x-axis) have an effect on the bonding of a specific active site. www.angelfire.com /falcon/cheesehead/reinhart.html   (852 words)

Allosteric transition pathways in the lactose repressor protein core domains: Asymmetric motions in a homodimer -- Flynn et al. 12 (11): 2523 -- Protein Science Daly, T.J. and Matthews, K.S. Allosteric regulation of inducer and operator binding to the lactose repressor. Allosteric transition pathways in the lactose repressor protein core domains: Asymmetric motions in a homodimer -- Flynn et al. Allosteric transition pathways in the lactose repressor protein core domains: Asymmetric motions in a homodimer www.proteinscience.org /cgi/content/full/12/11/2523   (7984 words)

Answer Key for Re In allosteric regulation, a metabolic pathway is controlled by an allosteric enzyme, which is normally an enzyme that catalyzes a reaction in the initial parts of a pathway. When the allosteric regulator is present in the allosteric site, the enzyme will either be in its active conformation or its inactive conformation, depending on whether the regulator is an inhibitor or an activator. An allosteric enzyme has at least one allosteric site, which is a site apart from the active site, to which the allosteric regulator bonds reversibly. www2.tltc.ttu.edu /dini/key2b(1403)00.htm   (652 words)

MOLECULAR BIOLOGY: ALLOSTERIC REGULATION OF RNA An important mechanism for controlling protein activity is allosteric regulation by a small molecule (i.e., binding of a small molecule to the protein at a location remote from the active site). In allosteric proteins, multiple subunits act cooperatively: Once a regulator is bound to one subunit, another subunit responds with dramatically enhanced affinity, allowing the protein's activity to be modulated as a function of slight changes in the regulator's concentration. Binding of this regulatory compound to the allosteric site induces structural rearrangements in the protein that are relayed to the active site, which then becomes either stable or unstable. scienceweek.com /2004/sc041119-1.htm   (1615 words)

Reverse Genetics of Escherichia coli Glycerol Kinase Allosteric Regulation and Glucose Control of Glycerol Utilization In Vivo -- Holtman et al. 183 (11): 3336 -- The Journal of Bacteriology Roles of glycerol kinase allosteric regulation in diauxic growth, glucose-glycerol utilization, and expression of glycerol kinase in the MC4100 genetic background. Reverse genetics is used to evaluate the roles in vivo of allosteric regulation of Escherichia coli glycerol kinase by the Allosteric regulation of glycerol kinase by enzyme III jb.asm.org /cgi/content/full/183/11/3336   (5618 words)

Pfam 18.0 : PyrI The regulatory chain is involved in allosteric regulation of aspartate carbamoyltransferase. ATCase from Erwinia herbicola differs from the other investigated enterobacterial ATCases by its absence of homotropic co-operativity toward the substrate aspartate and its lack of response to ATP which is an allosteric effector (activator) of this family of enzymes. In (c3)2(r2)3 ATCases, the association of the catalytic subunits c3 with the regulatory subunits r2 is responsible for the establishment of positive co-operativity between catalytic sites for the binding of aspartate and it dictates the pattern of allosteric response toward nucleotide effectors. pfam.wustl.edu /cgi-bin/getdesc?name=PyrI   (695 words)

Botany online: Physical Chemistry - Enzyme Catalysis - Regulation - Allosteric Enzymes Enzymes with co-operative effects are always built from several subunits (allosteric proteins). value of allosteric enzymes is consequently no constant, but a function of the substrate concentration. A positive co-operation generates a sigmoid curve expressing that the fist substrate molecule has been bound with a weak affinity while the following ones are bound by the other chains that are by now in a state of increased reactivity. www.biologie.uni-hamburg.de /b-online/e18/18f.htm   (627 words)

Allosteric regulation - Wikipedia, the free encyclopedia In biochemistry, allosteric regulation is the regulation of an enzyme or protein by binding an effector molecule at the protein's allosteric site (that is, a site other than the protein's active site). The sequential model of allosteric regulation holds that subunits are not connected in such a way that a conformational change in one induces a similar change in the others. Allosteric activation, such as the binding of oxygen molecules to hemoglobin, occurs when the binding of one ligand enhances the attraction between substrate molecules and other binding sites. en.wikipedia.org /wiki/Allosteric_modulation   (629 words)

Enzyme Regulation Allosteric regulation is achieved through noncovalent interactions (binding) of substrates and effectors to the enzyme. Allosteric regulation: regulation of enzyme activity through the binding of allosteric effectors that either activate (positive effectors) or inhibit (negative effectors) the activity of the enzyme: Enzymes subject to such regulation are called allosteric enzymes. www.people.virginia.edu /~rjh9u/IntroBio/bio201/lectures/Lecture14.html   (456 words)

401lec17p2.html Control of Enzyme Activity by Non-Covalent Modifiers is usually called allosteric regulation since the modifier binds to the enzyme at a site other than the active site but alters the shape of the active site. The binding sites for the allosteric modifier are shown as being remote from the active site. The allosteric enzyme is a dimer with identical subunits so it is called a homodimer (A-A, where 'A' represents one of the identical subunits). www.bio.mtu.edu /campbell/401lec17p2.html   (634 words)

Are the Common Allosteric Models Correct? For our purposes, allosteric refers to the regulation (either inhibition or activation) of enzyme activity due to the binding of a metabolite to a site on the enzyme that is different from the active site. An allosteric inhibitor binds to an allosteric site and shifts the conformational equilibrium to one that is relatively inactive. The purpose of the experiment is to determine if the individual allosteric sites (x-axis) have an effect on the bonding of a specific active site. www.angelfire.com /falcon/cheesehead/reinhart.html   (852 words)

Allosteric Regulation of Catalytic Activity: Escherichia coli Aspartate Transcarbamoylase versus Yeast Chorismate Mutase -- Helmstaedt et al. 65 (3): 404 -- Microbiology and Molecular Biology Reviews Carbamyl phosphate: an allosteric substrate for aspartate transcarbamylase of Escherichia coli. The residues which change their position during allosteric transition and thereby transduce the signal of effector binding from the allosteric to the active site are shown as stick models (green, carbon; blue, nitrogen; red, oxygen). Kinetics of the allosteric interactions of phosphofructokinase from Escherichia coli. mmbr.asm.org /cgi/content/full/65/3/404   (10340 words)

Regulation of Metabolism Tryptophan is the effector molecule for allosteric enzyme a. However, when the allosteric site is occupied by the effector molecule, the configuration of the active site is changed so that it is now unable to recognize and bind to its substrate (Figure 1). The effector molecule of certain allosteric enzymes binds to its allosteric site and consequently transforms the enzyme from an inactive to an active state (Figure 2). textbookofbacteriology.net /regulation.html   (3878 words)

Answer Key for Re In allosteric regulation, a metabolic pathway is controlled by an allosteric enzyme, which is normally an enzyme that catalyzes a reaction in the initial parts of a pathway. When the allosteric regulator is present in the allosteric site, the enzyme will either be in its active conformation or its inactive conformation, depending on whether the regulator is an inhibitor or an activator. An allosteric enzyme has at least one allosteric site, which is a site apart from the active site, to which the allosteric regulator bonds reversibly. www2.tltc.ttu.edu /dini/key2b(1403)00.htm   (652 words)

Allosteric Regulation of Catalytic Activity: Escherichia coli Aspartate Transcarbamoylase versus Yeast Chorismate Mutase -- Helmstaedt et al. 65 (3): 404 -- Microbiology and Molecular Biology Reviews Allosteric regulation of key metabolic enzymes is a fascinating field to study the structure-function relationship of induced Carbamyl phosphate: an allosteric substrate for aspartate transcarbamylase of Escherichia coli. The residues which change their position during allosteric transition and thereby transduce the signal of effector binding from the allosteric to the active site are shown as stick models (green, carbon; blue, nitrogen; red, oxygen). mmbr.asm.org /cgi/content/full/65/3/404   (652 words)

MOLECULAR BIOLOGY: ALLOSTERIC REGULATION OF RNA An important mechanism for controlling protein activity is allosteric regulation by a small molecule (i.e., binding of a small molecule to the protein at a location remote from the active site). Binding of this regulatory compound to the allosteric site induces structural rearrangements in the protein that are relayed to the active site, which then becomes either stable or unstable. In allosteric proteins, multiple subunits act cooperatively: Once a regulator is bound to one subunit, another subunit responds with dramatically enhanced affinity, allowing the protein's activity to be modulated as a function of slight changes in the regulator's concentration. scienceweek.com /2004/sc041119-1.htm   (1615 words)

Cell Biology Terms The allosteric property is useful in the regulation of enzyme activity. A regulatory enzyme whose activity is modified by the noncovalent binding of a particular metabolite at a site (the allosteric site) other than the active site. This may result in a conformational change at the active site so that the normal substrate cannot bind to it. www.mdstud.chalmers.se /~vivi/interests/biodict.html   (427 words)

Phosphoprotein inhibitor CPI-17 specificity depends on allosteric regulation of protein phosphatase-1 by regulatory subunits -- Eto et al. 101 (24): 8888 -- Proceedings of the National Academy of Sciences Phosphoprotein inhibitor CPI-17 specificity depends on allosteric regulation of protein phosphatase-1 by regulatory subunits -- Eto et al. association of MYPT1 with PP1C allosterically retards this hydrolysis, and, in response to agonists, Thr-38 is phosphorylated by protein www.pnas.org /cgi/content/abstract/101/24/8888   (427 words)

IngentaConnect The Cys292Ala Substitution in Protein R1 of Class I Ribonucleotid... Keywords: ribonucleotide reductase; allosteric regulation; site-directed mutagenesis; nucleotide binding; thioredoxin/glutaredoxin Protein R1, the homodimeric enzyme component which harbours binding sites for allosteric effectors (nucleoside triphosphates) as well as substrates (ribo-nucleoside diphosphates), has been engineered at Cys292 close to the dimer interaction area. Ribonucleotide reductase from aerobically grown Escherichia coli is allosterically regulated, both with respect to general activity and substrate specificity. www.ingentaconnect.com /content/bsc/ejb/1996/00000241/00000002/art00008   (269 words)

Metabolic and Autocrine Regulation of the Mammalian Target of Rapamycin by Pancreatic {beta}-Cells -- McDaniel et al. 51 (10): 2877 -- Diabetes potent allosteric activator of GDH at physiological concentrations. and allosteric activation of GDH by the ß-cell mitochondria decarboxylation pathway and allosteric activation of GDH by diabetes.diabetesjournals.org /cgi/content/full/51/10/2877   (269 words)

Abstract number: P2107 These results suggest a model in which heparin interacts with a regulatory exosite on human factor IXa that allosterically modulates catalysis through the S1-S3 subsites These results have implications for the antithrombotic mechanism of heparin, and potential in vivo regulation of intrinsic tenase by heparan sulfate. These data suggest that heparin interacts with an exosite on the factor IXa-substrate complex that modulates catalytic activity for both macromolecular and small peptide substrates. A marked resistance to inhibition of intrinsic tenase activity by heparin octasaccharide was also observed with R233A. www.schattauer.de /abstracts/absP2107.html   (269 words)

LEARNING OBJECTIVES Describe the reaction catalyzed by aspartate transcarbamoylase (ATCase), the regulation of ATCase by CTP and ATE and the biological significance of this regulation. Describe the experimental evidence for a concerted allosteric transition during the binding of substrate analogs to ATCase. Outline the effects of heterotropic and homotropic allosteric interactions on the equilibrium between the T and R forms of ATCase. home.snu.edu /dept/chemistry/SYLLABI/CHEM3133/LEARNI~1/CH10LE~1.HTM   (494 words)

4CellularComm.word This process is like allosteric modulation or regulation (described on page 136 in your text), except that it depends on the process of phosphorylation. This is not allosteric modulation which uses weak bonds to regulate the enzyme. The rate at which enzymes perform their functions can be increased or decreased by allosteric or covalent modulators. www.bio.davidson.edu /courses/Bio111/stdygd/upload/4CellularComm.word   (494 words)

20011217-mcb-01-glycogen.doc Describe the coordinated regulation of glycogen breakdown and glycogen synthesis, allosteric regulation and hormonally induced regulation via cAMP. Glycogenin then autocatalytically tacks on up to seven glucose residues (supplied as UDP-glucose; these reactions require Mg2+ as an inorganic cofactor), forming a “primer” for continued glycogen synthesis. Something interesting is that glycogenin and glycogen synthase are present in a 1:1 ratio — that is, they are intimately associated with each other. www-personal.umich.edu /~spark/notes/M1/mcb/20011217-mcb-01-glycogen.doc   (2820 words)

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