Subject:
All Disciplines Arts & Humanities Biology & Life Sciences Business & Economics Chemistry & Materials Science Computer Science & Mathematics Engineering Environmental & Earth Sciences Medicine & Pharmacology Physical Sciences Public Health & Healthcare Social Sciences
Sort:
Hottest Latest Alphabetical (A-Z) Alphabetical (Z-A)
Type:
All Topic Review Biography
Topic Review
Uncompetitive Inhibitor
Uncompetitive inhibition, also known as anti-competitive inhibition, takes place when an enzyme inhibitor binds only to the complex formed between the enzyme and the substrate (the E-S complex). Uncompetitive inhibition typically occurs in reactions with two or more substrates or products. While uncompetitive inhibition requires that an enzyme-substrate complex must be formed, non-competitive inhibition can occur with or without the substrate present. Uncompetitive inhibition is distinguished from competitive inhibition by two observations: first uncompetitive inhibition cannot be reversed by increasing [S] and second, as shown, the Lineweaver–Burk plot yields parallel rather than intersecting lines. This behavior is found in the inhibition of acetylcholinesterase by tertiary amines (R3N). Such compounds bind to the enzyme in its various forms, but the acyl-intermediate-amine complex cannot break down into enzyme plus product.
  • 18.3K
  • 16 Nov 2022
Biography
Greg Winter
Sir Gregory Paul Winter CBE FRS FMedSci (born 14 April 1951)[1][2] is a Nobel Prize-winning British biochemist best known for his work on the therapeutic use of monoclonal antibodies. His research career has been based almost entirely at the MRC Laboratory of Molecular Biology and the MRC Centre for Protein Engineering, in Cambridge, England. He is credited with invented techniques to both human
  • 1.5K
  • 16 Nov 2022
Topic Review
Compounds of Fluorine
Fluorine forms a great variety of chemical compounds, within which it always adopts an oxidation state of −1. With other atoms, fluorine forms either polar covalent bonds or ionic bonds. Most frequently, covalent bonds involving fluorine atoms are single bonds, although at least two examples of a higher order bond exist. Fluoride may act as a bridging ligand between two metals in some complex molecules. Molecules containing fluorine may also exhibit hydrogen bonding (a weaker bridging link to certain nonmetals). Fluorine's chemistry includes inorganic compounds formed with hydrogen, metals, nonmetals, and even noble gases; as well as a diverse set of organic compounds. For many elements (but not all) the highest known oxidation state can be achieved in a fluoride. For some elements this is achieved exclusively in a fluoride, for others exclusively in an oxide; and for still others (elements in certain groups) the highest oxidation states of oxides and fluorides are always equal.
  • 3.9K
  • 16 Nov 2022
Topic Review
Non-Covalent Interactions
A non-covalent interaction differs from a covalent bond in that it does not involve the sharing of electrons, but rather involves more dispersed variations of electromagnetic interactions between molecules or within a molecule. The chemical energy released in the formation of non-covalent interactions is typically on the order of 1-5 kcal/mol (1000–5000 calories per 6.02 x 10^23 molecules). Non-covalent interactions can be classified into different categories, such as electrostatic, π-effects, van der Waals forces, and hydrophobic effects. Non-covalent interactions are critical in maintaining the three-dimensional structure of large molecules, such as proteins and nucleic acids. In addition, they are also involved in many biological processes in which large molecules bind specifically but transiently to one another (see the properties section of the DNA page). These interactions also heavily influence drug design, crystallinity and design of materials, particularly for self-assembly, and, in general, the synthesis of many organic molecules. Intermolecular forces are non-covalent interactions that occur between different molecules, rather than between different atoms of the same molecule.
  • 1.5K
  • 16 Nov 2022
Topic Review
The Additive Manufacturing
The design of heat exchangers may change dramatically through the use of additive manufacturing (AM). Additive manufacturing, colloquially known as 3D printing, enables the production of monolithic metal bodies, devoid of contact resistance.
  • 467
  • 15 Nov 2022
Topic Review
Ratooning
Ratooning is the agricultural practice of harvesting a monocot crop by cutting most of the above-ground portion but leaving the roots and the growing shoot apices intact so as to allow the plants to recover and produce a fresh crop in the next season. This practice is widely used in the cultivation of crops such as rice, sugarcane, banana, and pineapple. Ratoon crops cannot be perennially renewed, and may be harvested only for a few seasons, as a decline in yield tends to occur due to increased crowding, damage by pests and diseases, and decreasing soil fertility.
  • 452
  • 15 Nov 2022
Topic Review
Polymeric Nanocomposite Membranes for Water Purification and Scalability
Water shortage is a major worldwide issue. Filtration using genuine polymeric membranes demonstrates excellent pollutant separation capabilities; however, polymeric membranes have restricted uses. Nanocomposite membranes, which are produced by integrating nanofillers into polymeric membrane matrices, may increase filtration. Carbon-based nanoparticles and metal/metal oxide nanoparticles have received the greatest attention.
  • 574
  • 15 Nov 2022
Topic Review
Cation–pi Interaction
Cation–π interaction is a noncovalent molecular interaction between the face of an electron-rich π system (e.g. benzene, ethylene, acetylene) and an adjacent cation (e.g. Li+, Na+). This interaction is an example of noncovalent bonding between a monopole (cation) and a quadrupole (π system). Bonding energies are significant, with solution-phase values falling within the same order of magnitude as hydrogen bonds and salt bridges. Similar to these other non-covalent bonds, cation–π interactions play an important role in nature, particularly in protein structure, molecular recognition and enzyme catalysis. The effect has also been observed and put to use in synthetic systems.
  • 474
  • 15 Nov 2022
Topic Review
Supercritical CO2
Supercritical CO2 (scCO2) is an alternative promising solvent that has been actively used in recent decades to simplify many processes of polymer synthesis, modification, decomposition, etc.
  • 842
  • 15 Nov 2022
Topic Review
Proton-Conducting Zirconates in Electrochemical Hydrogen Devices
Hydrogen-based energy can play a vital role in this aspect. This energy is green, clean, and renewable. Electrochemical hydrogen devices have been used extensively in nuclear power plants to manage hydrogen-based renewable fuel. Doped zirconate materials are commonly used as an electrolyte in these electrochemical devices. These materials have excellent physical stability and high proton transport numbers, which make them suitable for multiple applications. Doping enhances the physical and electronic properties of zirconate materials and makes them ideal for practical applications. 
  • 375
  • 15 Nov 2022
  • Page
  • of
  • 467
Featured Entry Collections
>>

Featured Books

>>
Encyclopedia of Social Sciences
Encyclopedia of COVID-19
Encyclopedia of Fungi
Encyclopedia of Digital Society, Industry 5.0 and Smart City
ScholarVision Creations
Feedback