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New mechanism discovered in meiosis

Inactivated, but still active– how modification of an enzyme governs critical processes in sexual reproduction.

Biology - Cell & Microbiology

May 03, 2013

5 / 5 (2)

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Study finds synergy in two approaches to breaking down cell walls of biomass

Enzymes could break down cell walls faster – leading to less expensive biofuels for transportation – if two enzyme systems are brought together in an industrial setting, new research by the Energy Department's National ...

Biology - Biotechnology

May 07, 2013

5 / 5 (1)

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New yeast strain could lower costs for cellulosic ethanol production

There's a lot that can be done with a corn cob after the kernels have been removed. Farmers leave the cobs on the field to boost soil quality. Enterprising cooks use the cobs to make jelly. In China, the ...

Biology - Biotechnology

May 03, 2013

4 / 5 (1)

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Turning up the heat on biofuels

(Phys.org) —The production of biofuels from lignocellulosic biomass would benefit on several levels if carried out at temperatures between 65 and 70 degrees Celsius. Researchers with the Energy Biosciences ...

Biology - Biotechnology

May 16, 2013

4 / 5 (1)

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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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