ENTRIES A–Z
Philip Winn in Dictionary of Biological Psychology, 2003
A term describing the interaction of a LIGAND and RECEPTOR; in biological psychology, when one discusses receptor binding one is referring to NEUROTRANSMITTERS or a DRUG acting at a receptor BINDING SITE on the MEMBRANE of a NEURON, though there are many other forms of chemical-receptor interaction that can be described (see, for example, STEREOCHEMICAL THEORY OF ODOUR DISCRIMINATION). Receptor binding occurs in a 'lock and key' manner: there are specific receptors to which specific molecules can bind. The stereochemical structure of a MOLECULE (see STEREOCHEMISTRY) will determine whether or not it can bind to a receptor. Note that normally one finds REVERSIBLE BINDING: that is, the receptor and ligand do not form permanent chemical bonds, but only weak ones that can easily be broken. IRREVERSIBLE BINDING, when a ligand forms a more or less permanent bond with a receptor can occur. Binding obeys the LAW OF MASS ACTION and should show a dose-effect relationship (see DOSE EFFECT CURVE).
Introduction To Receptors
John C. Matthews in Fundamentals of Receptor, Enzyme, and Transport Kinetics, 2017
The previous discussion has served to introduce several fundamentals of receptor theory. Receptor-ligand interactions involve physical contact between the receptor and the ligand.When receptor and ligand come together they tend to remain together for a finite period of time because of attractive forces that operate between the pair. In other words, the receptor and ligand have affinity for one another.Receptors exhibit specificity in their interactions with ligands. Only those ligands that “fit” and form an attractive force with the receptor will result in a successful interaction.In order for a receptor-ligand interaction to result in the production of a physiological effect the ligand must be capable of stimulating the receptor. The ligand must be an agonist.Receptor-ligand interactions are reversible.Receptor-ligand interactions are concentration dependent.
Pharmacokinetic Aspects of the in Vivo, Noninvasivestudy of Neuroreceptors in Man
William C. Eckelman, Lelio G. Colombetti in Receptor-Binding Radiotracers, 2017
Although ligands which have low equilibrium dissociation constants appear to have very slow clearance rates of the receptor-bound fraction, the differential distribution of the radioligand is not the result of a process at equilibrium, but of rate processes which are driven by the time-dependent concentration of the ligand in the blood. Therefore, it is more reasonable to expect that the clearance rate of receptor-bound ligand would be determined in large part by the intrinsic dissociation rate constant for the receptor-ligand complex. Fortunately, changes in the equilibrium dissociation constant from one ligand to another are largely the result of changes in the dissociation rate constant, whereas the association rate constant remains fairly constant.13 Therefore, either the equilibrium dissociation constant or the dissociation rate constant may be used as an approximate indicator of the clearance rate of receptor-bound ligand. However, changes in these two constants do not always precisely correspond for the ligands of interest here so that one should in principle use the dissociation rate constant to predict which ligands will prove optimal for the method.14,15 As only a few ligands have been tested in vivo for the opiate and dopamine systems, it is difficult to state with certainty which parameter or parameters are most important and future investigations using a variety of ligands labeled with gamma-emitting radioisotopes should clarify this problem.
Virtual screening for potential inhibitors of β(1,3)-D-glucan synthase as drug candidates against fungal cell wall
Published in Journal of Drug Assessment, 2020
Zinat Farhadi, Tayebeh Farhadi, Seyed MohammadReza Hashemian
In order to select the leads as hopeful drug candidates, “binding energy” between each molecule (ligand) and the receptor can be a suitable criterion and calculated through docking analysis20. Overall, evaluation of some factors such as “binding energy” and “number of hydrogen bonds” between ligands and their receptors has been interpreted as a computational filtering method to limit the number of drug candidates for experimental analysis16. The degree of ligand-receptor binding refers to the binding affinity. The energy released due to the bond formation or, rather, interaction of the ligand and protein is termed in the form of binding energy. The free energy of a favorable reaction is negative. Lesser the binding energy, the better is the binding of the ligand and protein16,21–27. In this study, the virtual screening software was employed to screen a library of agents against the protein receptor, 1,3-β-D-glucan synthase. The results of this study may be promising in the field of discovering and designing novel drug candidates against fungal infections.
PPARγ induces PD-L1 expression in MSS+ colorectal cancer cells
Published in OncoImmunology, 2021
Tobias Gutting, Veronika Hauber, Jens Pahl, Kay Klapproth, Wenyue Wu, Ioana Dobrota, Frank Herweck, Juliane Reichling, Laura Helm, Torsten Schroeder, Beifang Li, Philip Weidner, Tianzuo Zhan, Maximilian Eckardt, Johannes Betge, Sebastian Belle, Carsten Sticht, Timo Gaiser, Michael Boutros, Matthias P.A. Ebert, Adelheid Cerwenka, Elke Burgermeister
However, the effects of PPARγ agonists cannot be attributed to PD-L1 upregulation alone, instead a plethora of target genes contributes to growth inhibition complemented by non-genomic receptor-independent effects (e.g. on mitochondria). Overall, pio was the weaker and more transiently active agonist than rosi in our assays. This may be due to different pharmacological stability of the agent in the medium, cells or MatriGel®.32 We also used high concentrations of glitazones (µM) to guarantee diffusion and permeability in 3D matrices; thus, translatability of the observed in vitro data is warranted. In other words, the pleiotropic targets of transcription factors driven by interferons and PPAR ligands, affecting the transcriptomes of both immune and epithelial cells (e.g. cell cycle regulator P21), shall culminate in a common outcome, i.e. reduced viability and/or proliferation of tumor stem cells.11 Since morphological and functional phenotypes of PDOs and LAK are mutually influenced in a bidirectional cross-talk in the cocultures and the real-life tumor microenvironment, future in-depth dissection of cell type-specific PPAR-dependent vs. ligand-mediated mechanisms are necessary.
Radio-protective efficacy of Gymnema sylvestre on Pangasius sutchi against gamma (60Co) irradiation
Published in International Journal of Radiation Biology, 2022
Pamela Sinha, Kantha Devi Arunachalam, Santhosh Kumar Nagarajan, Thirumurthy Madhavan, Arumugam R. Jayakumar, Mohamed Saiyad Musthafa
Binding energies in the protein-ligand interactions explains how ligand fits with target protein. Examination of the binding interactions of the ligands helps in elucidating the reasonable and appropriate structural features of ligand which increase the binding affinity and therapeutic efficacy. Hence through in-silico studies it may be concluded that Ami and the phyto-components of GS can be used as a novel drug as radioprotector for protecting DNA from radiation but these phyto-components of GS cannot effective for DNA repair mechanism compare to Ami. Similarly, Vinutha et al. (2015) have mentioned that the P. marsupium on pBR322 plasmid DNA and its in-silico studies showed the components of P. marsupium inhibited p53 protein by binding to Arginine 248 and Arginine 273 amino acid, which revealed that the components of P. marsupium can protect DNA from radiation-induced damage. These reports support the current study on radio-protective efficacy of Ami and phyto-components of GS in P. sutchi which can further lead to the higher studies on animal or human model. In order to validate the docking program followed, we have performed docking of Pifithrin-α (PFT-α) hydrobromide with p53 structure 1TUP. PFT-α hydrobromide is a p53 inhibitor which blocks the activation of transcription and apoptosis by p53. We have observed that PFT-α hydrobromide docked in the same binding space as that of other ligands.
Related Knowledge Centers
- Binding Site
- Biochemistry
- Biomolecule
- Cell Signaling
- Molecule
- Protein
- Pharmacology
- Coordination Complex
- Molecular Binding
- Conformational Isomerism