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[1] If a given enzyme has a high chemical specificity, this means that the set of ligands to which it binds is limited, such that neither binding events nor catalysis can occur at an appreciable rate with additional molecules. An example of a protein-ligand pair whose binding activity can be highly specific is the antibody-antigen system. [2]
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. [ 2 ] 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 .
If the true status of the condition cannot be known, sensitivity and specificity can be defined relative to a "gold standard test" which is assumed correct. For all testing, both diagnoses and screening, there is usually a trade-off between sensitivity and specificity, such that higher sensitivities will mean lower specificities and vice versa.
The relationship between sensitivity and specificity, as well as the performance of the classifier, can be visualized and studied using the Receiver Operating Characteristic (ROC) curve. In theory, sensitivity and specificity are independent in the sense that it is possible to achieve 100% in both (such as in the red/blue ball example given above).
A ligand binding assay (LBA) is an assay, or an analytic procedure, which relies on the binding of ligand molecules to receptors, antibodies or other macromolecules. [1] A detection method is used to determine the presence and amount of the ligand-receptor complexes formed, and this is usually determined electrochemically or through a fluorescence detection method. [2]
They use the sensitivity and specificity of the test to determine whether a test result usefully changes the probability that a condition (such as a disease state) exists. The first description of the use of likelihood ratios for decision rules was made at a symposium on information theory in 1954. [1]
The Hammett equation (Equation 1) provides the relationship between the substituent on the benzene ring and the ionizing rate constant of the reaction. Hammett used the ionization of benzoic acid as the standard reaction to define a set of substituent parameters σ X , and then to generate the ρ values, which represent ionizing abilities of ...
The Taft equation is a linear free energy relationship (LFER) used in physical organic chemistry in the study of reaction mechanisms and in the development of quantitative structure–activity relationships for organic compounds. It was developed by Robert W. Taft in 1952 [2] [3] [4] as a modification to the Hammett equation. [5]