Catalytic Center
Catalytic Center - Related Videos
08:56
Catalytic Reactor: Hydrogenation of Ethylene
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2023
Source: Kerry M. Dooley and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA The hydrogenation of ethylene (C2H4) to ethane (C2H6) has often been studied as a model reduction reaction in characterizing new metal catalysts.1-2 While supported nickel is not the most active metal catalyst for this reaction, it is active enough that reaction can take place at < 200°C. The reaction typically involves adsorbed, dissociated hydrogen (H2) reacting...
06:50
Preparation and 3D Tracking of Catalytic Swimming Devices
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Cited by 1 •
2016
A method to prepare catalytically active Janus colloids that can "swim" in fluids and determine their 3D trajectories is presented.
01:07
Catalytically Perfect Enzymes
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2023
The theory of catalytically perfect enzymes was first proposed by W.J. Albery and J. R. Knowles in 1976. These enzymes catalyze biochemical reactions at high-speed. Their catalytic efficiency values range from 108-109 M-1s-1. These enzymes are also called 'diffusion-controlled' as the only rate-limiting step in the catalysis is that of the substrate diffusion into the active site. Examples include triose phosphate isomerase, fumarase, and superoxide dismutase. Most enzymes achieve catalytic...
01:19
Turnover Number and Catalytic Efficiency
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2023
The turnover number of an enzyme is the maximum number of substrate molecules it can transform per unit time. Turnover numbers for most enzymes range from 1 to 1000 molecules per second. Catalase has the known highest turnover number, capable of converting up to 2.8×106 molecules of hydrogen peroxide into water and oxygen per second. Lysozyme has the lowest known turnover number of half a molecule per second. Chymotrypsin is a pancreatic enzyme that breaks down proteins during digestion. The...
02:33
Lattice Centering and Coordination Number
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2020
The structure of a crystalline solid, whether a metal or not, is best described by considering its simplest repeating unit, which is referred to as its unit cell. The unit cell consists of lattice points that represent the locations of atoms or ions. The entire structure then consists of this unit cell repeating in three dimensions. The three different types of unit cells present in the cubic lattice are illustrated in Figure 1. Types of Unit Cells Imagine taking a large number of identical...
FAQs
The three-dimensional arrangement positions substrates in a productive orientation and places reactive amino acid residues, metal ions, or other cofactors where they can support the reaction. This organization helps stabilize reaction intermediates and lowers the activation energy. Consequently, structural changes within the region can affect both how efficiently an enzyme catalyzes a reaction and which substrates it recognizes.
Amino acid residues can participate directly in the reaction, while metal ions or other cofactors can support catalysis by helping stabilize reaction intermediates. Their effects depend on their precise placement within the catalytic center. Examining these components helps researchers connect the molecular structure of an enzyme or ribozyme with its reaction mechanism and catalytic performance.
Mutations can alter the three-dimensional arrangement or the identity of components that support catalysis. Such changes may disrupt substrate orientation, modify the contribution of specific amino acid residues, or affect interactions with metal ions and other cofactors. Studying these effects helps explain why an altered enzyme may show changes in catalytic activity or substrate specificity.
Analysis can reveal how substrate specificity arises, which components participate in the reaction, and how the center stabilizes reaction intermediates. It can also clarify how structural changes influence catalytic activity. These insights connect molecular features to biological function and provide a basis for understanding reaction mechanisms in enzymes and ribozymes.
A focused investigation considers the center's three-dimensional arrangement, the substrate orientation it creates, and the roles of amino acid residues, metal ions, or other cofactors. Researchers can then relate these features to reaction acceleration, specificity, and the effects of mutations. This approach organizes structural and functional information around the molecular region most directly involved in catalysis.
Understanding the components and reaction mechanisms of catalytic centers supports the design of enzyme inhibitors and therapeutic agents that influence biological catalysis. The same knowledge can guide the engineering of biocatalysts with useful catalytic properties. In biology and medicine, these applications depend on connecting molecular structure with specificity, activity, and the consequences of altered function.