Related topics: protein · cells · bacteria · chemical reactions · cancer

Keeping a vigilant watch on SARS-CoV-2

New lateral flow test Vigilant is cheaper, easier to use and as reliable as the current gold standard PCR test for diagnosing SARS-CoV-2 infection.

Detoxifiers from the landfill

The production of chemicals is a cumbersome business. Often, only a small part of what is actually wanted is produced in the factory. The large remainder is unusable—or even worse. Examples? The defoliant "Agent Orange" ...

Self-healing concrete could multiply lifespans of structures

Researchers at Worcester Polytechnic Institute (WPI) are using an enzyme found in red blood cells to create self-healing concrete that is four times more durable than traditional concrete, extending the life of concrete-based ...

Enzymes successfully embedded in plastics

In general, plastics are processed at way over a hundred degrees Celsius. Enzymes, by contrast, cannot usually withstand these high temperatures. Researchers at the Fraunhofer Institute for Applied Polymer Research IAP have ...

Newly discovered enzymes are not heavy metal fans

Carbonic anhydrases are essential enzymes that are present in virtually all living things; all eight classes of carbonic anhydrases that have been identified to date need a metal ion to function. But now, researchers from ...

Genome mining leads to a new type of peptide prenylation

Researchers from NUS used a genome mining approach to identify a new cyclic peptide (tolypamide) derived from a cyanobacterium. The biosynthesis of tolypamide features a new type of enzyme that is able to prenylate a range ...

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Enzyme

Enzymes are biomolecules that catalyze (i.e., increase the rates of) chemical reactions. Nearly all known enzymes are proteins. However, certain RNA molecules can be effective biocatalysts too. These RNA molecules have come to be known as ribozymes. In enzymatic reactions, the molecules at the beginning of the process are called substrates, and the enzyme converts them into different molecules, called the products. Almost all processes in a biological cell need enzymes to occur at significant rates. Since enzymes are selective for their substrates and speed up only a few reactions from among many possibilities, the set of enzymes made in a cell determines which metabolic pathways occur in that cell.

Like all catalysts, enzymes work by lowering the activation energy (Ea or ΔG‡) for a reaction, thus dramatically increasing the rate of the reaction. Most enzyme reaction rates are millions of times faster than those of comparable un-catalyzed reactions. As with all catalysts, enzymes are not consumed by the reactions they catalyze, nor do they alter the equilibrium of these reactions. However, enzymes do differ from most other catalysts by being much more specific. Enzymes are known to catalyze about 4,000 biochemical reactions. A few RNA molecules called ribozymes catalyze reactions, with an important example being some parts of the ribosome. Synthetic molecules called artificial enzymes also display enzyme-like catalysis.

Enzyme activity can be affected by other molecules. Inhibitors are molecules that decrease enzyme activity; activators are molecules that increase activity. Many drugs and poisons are enzyme inhibitors. Activity is also affected by temperature, chemical environment (e.g., pH), and the concentration of substrate. Some enzymes are used commercially, for example, in the synthesis of antibiotics. In addition, some household products use enzymes to speed up biochemical reactions (e.g., enzymes in biological washing powders break down protein or fat stains on clothes; enzymes in meat tenderizers break down proteins, making the meat easier to chew).

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