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
Catalyst mystery unlocked
Aug 18, 2008 |
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Different keys are not supposed to fit the same lock, but in biological systems multiple versions of a catalyst all make a reaction go, according to a new study that explains the phenomenon. Scheduled for online publication ...
Scientists develop first examples of RNA that replicates itself indefinitely
Jan 09, 2009 |
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Now, a pair of Scripps Research Institute scientists has taken a significant step toward answering that question. The scientists have synthesized for the first time RNA enzymes that can replicate themselves without the help ...
Scientists identify enzyme important in aging
Jul 10, 2009 |
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The secret to longevity may lie in an enzyme with the ability to promote a robust immune system into old age by maintaining the function of the thymus throughout life, according to researchers studying an "anti-aging" mouse ...
Scientists present first genetic evidence for why placebos work
Jul 20, 2009 |
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usually mere sugar pills designed to represent "no treatment" in a clinical treatment study. The effectiveness of the actual medication is compared with the placebo to determine if the medication works.
Field-hospital-on-a-chip project awarded to nanoengineer from UC San Diego
Nanotechnology / Bio & Medicine
Oct 23, 2008 |
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With a $1.6M grant from the U.S. Office of Naval Research (ONR), UC San Diego NanoEngineering professor Joseph Wang will lead a project to create a "field hospital on a chip" that soldiers can wear on the ...
Experimental TB drug explodes bacteria from the inside out
Medicine & Health / Medications
Nov 27, 2008 |
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An international team of biochemists has discovered how an experimental drug unleashes its destructive force inside the bacteria that cause tuberculosis (TB). The finding could help scientists develop ways to treat dormant ...
New piece found in the puzzle of epigenetics
Jun 16, 2009 |
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For many years scientists have known that the numerous biological functions of an organism are not regulated solely by the DNA sequence of its genes: Superordinate regulatory mechanisms exist that contribute to determining ...
Atomic-resolution views suggest function of enzyme that regulates light-detecting signals in eye
Oct 07, 2008 |
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An atomic-resolution view of an enzyme found only in the eye has given researchers at the University of Washington (UW) clues about how this enzyme, essential to vision, is activated. The enzyme, phosphodiesterase ...
Scientists create new enzymes for biofuel production
Mar 23, 2009 |
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Researchers at the California Institute of Technology (Caltech) and world-leading gene-synthesis company DNA2.0 have taken an important step toward the development of a cost-efficient process to extract sugars ...
Lab-on-a-Chip Performs 1,000 Chemical Reactions At Once
Chemistry / Analytical Chemistry
Sep 27, 2009 |
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Flasks, beakers, and hot plates may soon be a thing of the past in medicinal chemistry labs. Instead of handling a few experiments on a benchtop, scientists may simply pop a microchip into a computer and instantly run thousands ...
Researchers unravel mystery behind long-lasting memories
Medicine & Health / Neuroscience
Aug 11, 2009 |
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A new study by researchers at Wake Forest University School of Medicine may reveal how long-lasting memories form in the brain.
Einstein researchers develop novel antibiotics that don't trigger resistance
Mar 13, 2009 |
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Bacterial resistance to antibiotics is one of medicine's most vexing challenges. In a study described in Nature Chemical Biology, researchers from Albert Einstein College of Medicine of Yeshiva University are de ...
Scientists successfully reprogram blood cells
Nov 09, 2009 |
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Researchers have transplanted genetically modified hematopoietic stem cells into mice so that their developing red blood cells produce a critical lysosomal enzyme -preventing or reducing organ and central nervous system damage ...
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.
Microbes to Take Over Ethanol Production?
Nov 20, 2009 |
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(PhysOrg.com) -- Not too long ago, it seemed that ethanol production was the wave of the future. The use of trash, wood chips or different types of plants -- usually grass or corn -- to make ethanol was considered ...
