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

Breakthrough in harnessing the power of biological catalysts

The power of nature could soon be used to create day-to-day materials such as paints, cosmetics and pharmaceuticals in a much more environmentally friendly way, thanks to a new breakthrough from scientists.

Sweet success of parasite survival could also be its downfall

University of York scientists from the Department of Chemistry are part of an international team which has discovered how a parasite responsible for spreading a serious tropical disease protects itself from starvation once ...

A molecular string phone at work

Researchers from the Department of Atomically Resolved Dynamics of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg, the University of Potsdam ...

Method to customize microbes for better biofuel production

Scientists at the US Department of Energy's Oak Ridge National Laboratory have demonstrated a method to insert genes into a variety of microorganisms that previously would not accept foreign DNA, with the goal of creating ...

Analyzing poppies to make better drugs

A team of researchers from the University of Calgary has uncovered new information about a class of plant enzymes that could have implications for the pharmaceutical industry.

Cleaning up hydrogen peroxide production

The most common process for making hydrogen peroxide begins with a highly toxic, flammable working solution that is combined with hydrogen, filtered, combined with oxygen, mixed in water, and then concentrated to extremely ...

Structure of protein nanoturbine revealed

Cells rely on protein complexes known as ATP synthases or ATPases for their energy needs. Adenosine triphosphate (ATP) molecules power most of the processes sustaining life. Structural biologist Professor Leonid Sazanov and ...

Antacid helps tuberculosis bacteria to survive

In 2017, some 10 million people suffered from tuberculosis and 1.6 million died of the disease. One reason that infection with Mycobacterium tuberculosis is so difficult to treat is because the bacteria can hide inside immune ...

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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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