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Hub AI
Binding selectivity AI simulator
(@Binding selectivity_simulator)
Hub AI
Binding selectivity AI simulator
(@Binding selectivity_simulator)
Binding selectivity
In chemistry, binding selectivity is defined with respect to the binding of ligands to a substrate forming a complex. Binding selectivity describes how a ligand may bind more preferentially to one receptor than another. A selectivity coefficient is the equilibrium constant for the reaction of displacement by one ligand of another ligand in a complex with the substrate. Binding selectivity is of major importance in biochemistry and in chemical separation processes.
The concept of selectivity is used to quantify the extent to which one chemical substance, A, binds each of two other chemical substances, B and C. The simplest case is where the complexes formed have 1:1 stoichiometry. Then, the two interactions may be characterized by equilibrium constants KAB and KAC. where [X] represents the concentration of substance X (A, B, C, …).
![{\displaystyle {\begin{aligned}{\mathrm {A} {}+{}\mathrm {B} {}\mathrel {\longrightleftharpoons } {}\mathrm {AB} };&\quad K_{\rm {AB}}={\frac {[{\mathrm {AB} }]}{[\mathrm {A} ][\mathrm {B} ]}}\\{\mathrm {A} {}+{}\mathrm {C} {}\mathrel {\longrightleftharpoons } {}\mathrm {AC} };&\quad K_{\rm {AC}}={\frac {[\mathrm {AC} ]}{[\mathrm {A} ][\mathrm {C} ]}}\end{aligned}}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/09507c356d20cb14433bfe49b7c65ac174e703bc)
A selectivity coefficient is defined as the ratio of the two equilibrium constants. This selectivity coefficient is in fact the equilibrium constant for the displacement reaction
![{\displaystyle {\mathrm {AB} {}+{}\mathrm {C} {}\mathrel {\longrightleftharpoons } {}\mathrm {AC} {}+{}\mathrm {B} };\quad K_{\rm {B,C}}={\frac {[\mathrm {AC} ][\mathrm {B} ]}{[\mathrm {AB} ][\mathrm {C} ]}}={\frac {K_{\rm {AC}}{[\mathrm {A} ][\mathrm {B} ][\mathrm {C} ]}}{K_{\rm {AB}}{[\mathrm {A} ][\mathrm {B} ][\mathrm {C} ]}}}={\frac {K_{\rm {AC}}}{K_{\rm {AB}}}}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/d3e66a621cce2b44770261beab94c415a5351b26)
It is easy to show that the same definition applies to complexes of a different stoichiometry, ApBq and ApCq. The greater the selectivity coefficient, the more the ligand C will displace the ligand B from the complex formed with the substrate A. An alternative interpretation is that the greater the selectivity coefficient, the lower the concentration of C that is needed to displace B from AB. Selectivity coefficients are determined experimentally by measuring the two equilibrium constants, KAB and KAC.
In biochemistry the substrate is known as a receptor. A receptor is a protein molecule, embedded in either the plasma membrane or the cytoplasm of a cell, to which one or more specific kinds of signalling molecules may bind. A ligand may be a peptide or another small molecule, such as a neurotransmitter, a hormone, a pharmaceutical drug, or a toxin. The specificity of a receptor is determined by its spatial geometry and the way it binds to the ligand through non-covalent interactions, such as hydrogen bonding or Van der Waals forces.
If a receptor can be isolated a synthetic drug can be developed either to stimulate the receptor, an agonist or to block it, an antagonist. The stomach ulcer drug cimetidine was developed as an H2 antagonist by chemically engineering the molecule for maximum specificity to an isolated tissue containing the receptor. The further use of quantitative structure-activity relationships (QSAR) led to the development of other agents such as ranitidine.
"Selectivity" when referring to a drug is relative. For example, in a higher dose, a specific drug molecule may also bind to other receptors than those said to be "selective".
Binding selectivity
In chemistry, binding selectivity is defined with respect to the binding of ligands to a substrate forming a complex. Binding selectivity describes how a ligand may bind more preferentially to one receptor than another. A selectivity coefficient is the equilibrium constant for the reaction of displacement by one ligand of another ligand in a complex with the substrate. Binding selectivity is of major importance in biochemistry and in chemical separation processes.
The concept of selectivity is used to quantify the extent to which one chemical substance, A, binds each of two other chemical substances, B and C. The simplest case is where the complexes formed have 1:1 stoichiometry. Then, the two interactions may be characterized by equilibrium constants KAB and KAC. where [X] represents the concentration of substance X (A, B, C, …).
A selectivity coefficient is defined as the ratio of the two equilibrium constants. This selectivity coefficient is in fact the equilibrium constant for the displacement reaction
It is easy to show that the same definition applies to complexes of a different stoichiometry, ApBq and ApCq. The greater the selectivity coefficient, the more the ligand C will displace the ligand B from the complex formed with the substrate A. An alternative interpretation is that the greater the selectivity coefficient, the lower the concentration of C that is needed to displace B from AB. Selectivity coefficients are determined experimentally by measuring the two equilibrium constants, KAB and KAC.
In biochemistry the substrate is known as a receptor. A receptor is a protein molecule, embedded in either the plasma membrane or the cytoplasm of a cell, to which one or more specific kinds of signalling molecules may bind. A ligand may be a peptide or another small molecule, such as a neurotransmitter, a hormone, a pharmaceutical drug, or a toxin. The specificity of a receptor is determined by its spatial geometry and the way it binds to the ligand through non-covalent interactions, such as hydrogen bonding or Van der Waals forces.
If a receptor can be isolated a synthetic drug can be developed either to stimulate the receptor, an agonist or to block it, an antagonist. The stomach ulcer drug cimetidine was developed as an H2 antagonist by chemically engineering the molecule for maximum specificity to an isolated tissue containing the receptor. The further use of quantitative structure-activity relationships (QSAR) led to the development of other agents such as ranitidine.
"Selectivity" when referring to a drug is relative. For example, in a higher dose, a specific drug molecule may also bind to other receptors than those said to be "selective".