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Uniquely shaped enzyme amazes chemists

Chemists of Radboud University Nijmegen have found that a uniquely shaped enzyme that has never been seen before in biology is real: two interlocked ring structures, known as catenanes . The results have ...

Chemistry - Materials Science

18 hours ago

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Researchers unearth bioenergy potential in leaf-cutter ant communities

As spring warms up Wisconsin, humans aren't the only ones tending their gardens. At the University of Wisconsin–Madison Department of Bacteriology, colonies of leaf-cutter ants cultivate thriving communities ...

Biology - Cell & Microbiology

Jun 14, 2013

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Novel enzyme from tiny gribble could prove a boon for biofuels research

(Phys.org) —Researchers from the United Kingdom, the Energy Department's National Renewable Energy Laboratory (NREL), and the University of Kentucky have recently published a paper describing a novel cellulose-degrading ...

Biology - Biotechnology

Jun 12, 2013

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Head in a cage: Fatty acid composition of diacylglycerols determines local signaling patterns

(Phys.org) —In the human body, lipids do not only serve as energy stores and structural elements, but they are also important signaling molecules. Disruptions of lipid signal transmission seem to be involved ...

Chemistry - Biochemistry

Jun 12, 2013

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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).

This text uses material from Wikipedia, licensed under CC BY-SA

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