Related topics: proceedings of the national academy of sciences , genes , protein
Enzyme
hideEnzymes 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).
For more information about Enzyme, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with enzyme
Scientists take a step towards uncovering the histone code
Dec 20, 2009 |
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Researchers at Emory University School of Medicine have determined the structures of two enzymes that customize histones, the spool-like proteins around which DNA coils inside the cell.
Making New Enzymes to Engineer Plants for Biofuel Production
Dec 21, 2009 |
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(PhysOrg.com) -- Brookhaven scientists have created a new enzyme with the potential to interfere with a key cell-wall component in plants, possibly leading to plants that are easier to "digest" and convert ...
Research project yields better understanding of the defective protein that causes cystic fibrosis
Dec 18, 2009 |
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A team of researchers studying the protein that, when defective or absent, causes cystic fibrosis (CF) has made an important discovery about how that protein is normally controlled and under what circumstances ...
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Mutant CTRC gene has a new way to trigger pancreatitis
7 hours ago |
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(PhysOrg.com) -- The CTRC gene is a lot like your baby brother—mutant and annoying. Drs. Miklos Sahin-Toth and Richard Szmola of the Department of Molecular & Cell Biology at Boston University Henry M. Goldman School of Dental ...
Scientists take important step toward the proverbial fountain of youth
9 hours ago |
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Going back for a second dessert after your holiday meal might not be the best strategy for living a long, cancer-free life say researchers from the University of Alabama at Birmingham. That's because they've shown exactly ...
Enzyme necessary for development of healthy immune system
11 hours ago |
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Mice without the deoxycytidine kinase (dCK) enzyme have defects in their adaptive immune system, producing very low levels of both T and B lymphocytes, the major players involved in immune response, according to a study by ...
Meddling in mosquitoes' sex lives could help stop the spread of malaria, says study
17 hours ago |
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(PhysOrg.com) -- Stopping male mosquitoes from sealing their sperm inside females with a 'mating plug' could prevent mosquitoes from reproducing, and offer a potential new way to combat malaria, say scientists ...
Compound found to safely counter deadly bird flu
Dec 21, 2009 |
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The specter of a drug-resistant form of the deadly H5N1 avian influenza is a nightmare to keep public health officials awake at night.
Molecular freight: Synthetic nanoscale transport system modeled on nature
Dec 21, 2009 |
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(PhysOrg.com) -- Just like our roads, there is a lot of traffic within the cells in our bodies, because cell components, messenger molecules, and enzymes must also be brought to the right places in the cell. One of these ...
Disparity in use of implantable devices to prevent sudden death in heart failure patients
Dec 18, 2009 |
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A study of heart failure patients who meet national guidelines for devices that stabilize and strengthen the heart's electrical system found that only half of eligible patients received the devices. The study, which is the ...
Researchers link calorie intake to cell lifespan, cancer development (w/ Video)
Dec 17, 2009 |
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Researchers from the University of Alabama at Birmingham (UAB) have discovered that restricting consumption of glucose, the most common dietary sugar, can extend the life of healthy human-lung cells and speed ...
Soil Microorganisms? Role Cited as a Missing Factor in Climate Change Equation
Dec 17, 2009 |
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(PhysOrg.com) -- Those seeking to understand and predict climate change can now use an additional tool to calculate carbon dioxide exchanges on land, according to a scientific journal article co-authored by a University of ...
Gene linked to a rare form of progressive hearing loss in males is identified
Dec 17, 2009 |
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A gene associated with a rare form of progressive deafness in males has been identified by an international team of researchers funded by the National Institute on Deafness and Other Communication Disorders. The gene, PRPS1, ...
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