Substrate Affinity
Substrate Affinity - Related Videos
03:07
Electron Affinity
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2020
The electron affinity (EA) is the energy change for adding an electron to a gaseous atom to form an anion (negative ion). This process can be either endothermic or exothermic, depending on the element. Many of these elements have negative values of EA, which means that energy is released when the gaseous atom accepts an electron. However, for some elements, energy is required for the atom to become negatively charged, and the value of their EA is positive. Just as with ionization energy,...
01:41
Affinity and Avidity
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2019
Overview Antibodies bind to toxins or substances on the surface of cells, bacteria, viruses, or fungi. The substance is called an antigen, and the precise binding site is the epitope. The strength of the antibody-epitope interaction is called affinity. When an antibody binds an antigen by multiple epitopes, the cumulative strength of the interaction is called avidity. The strength of the interaction influences the elicited immune response. The Adaptive Immune System Increases Efficiency by...
13:58
Probing C84-embedded Si Substrate Using Scanning Probe Microscopy and Molecular Dynamics
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Cited by 1 •
2016
This paper reports the nanomaterial fabrication of a fullerene Si substrate inspected and verified by nanomeasurements and molecular dynamic simulation.
01:03
Affinity Chromatography
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2024
Affinity chromatography is a powerful technique extensively utilized for separating and purifying specific biomolecules from complex mixtures. It capitalizes on the highly selective binding between an analyte and its counterpart, such as antibody-antigen interactions. The counterpart is immobilized on the stationary phase, forming an affinity column. The stationary phase typically consists of solid support, such as agarose or porous glass beads, immobilizing the affinity ligand. The mobile...
02:21
Purification of Viral Integrase Using Heparin Affinity Chromatography
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2026
Source: Lopez Jr., M. et al. Detection and Removal of Nuclease Contamination During Purification of Recombinant Prototype Foamy Virus Integrase. J. Vis. Exp. (2017)This video demonstrates the procedure for purifying viral integrase from bacterial nuclease contamination using heparin Sepharose column chromatography followed by SDS-PAGE analysis to confirm protein purity.
FAQs
An enzyme favors substrates whose shape fits the active site and whose charges and chemical groups support complementary interactions. These contacts influence whether binding is sufficiently favorable for the enzyme to distinguish one substrate from another. Because substrate recognition affects reaction specificity and catalytic efficiency, changes in active-site complementarity can alter which reactions an enzyme performs most effectively.
Under defined experimental conditions, a lower Michaelis constant, or Km, generally indicates stronger apparent affinity for the substrate. Km provides a way to compare how enzymes or enzyme variants behave in Michaelis–Menten kinetics, but its interpretation remains tied to the conditions used for measurement. Comparisons are therefore most meaningful when those conditions are consistent.
Environmental conditions can modify binding behavior by changing how the enzyme and substrate interact. Variations in pH, temperature, or ionic strength may alter the effectiveness of charge-based and other chemical interactions at the active site. Consequently, an enzyme may show different apparent affinity under different conditions, making environmental control important when interpreting experimental comparisons.
Comparing affinity for different substrates helps reveal an enzyme’s preferences and its role in metabolic pathways. A mutation that changes the active site may alter shape, charge, or chemical complementarity, which can shift apparent affinity and catalytic efficiency. Measuring these changes allows researchers to connect sequence-level alterations with functional differences in enzyme behavior.
Researchers measure enzyme behavior with selected substrates under defined conditions and analyze the results using Michaelis–Menten kinetics. The resulting Km values provide experimental indicators for comparing apparent affinity, while consistent pH, temperature, and ionic strength improve the fairness of comparisons. This approach can distinguish substrate preferences or reveal altered behavior in enzyme variants.
Affinity measurements support metabolic-pathway analysis, enzyme characterization, and evaluation of mutations. They also help researchers optimize biotechnology processes, drug development efforts, and diagnostic assays by identifying useful enzyme-substrate preferences and comparing performance under selected conditions. In each setting, the measurements connect binding behavior with practical decisions about enzyme selection, modification, or experimental design.