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

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MIT and Harvard University chemists have discovered the structure of an unusual bacterial enzyme that can break down an amino acid found in collagen, which is the most abundant protein in the human body.

Chemists create new artificial enzyme

Enzymes are nature's powerhouses. Found in the cells of all animals, plants, and every other living organism, they accelerate the chemical reactions that trigger thousands of biological functions—from forming neurons to ...

Chemists inhibit a critical gear of cell immortality

One of the hallmarks of cancer is cell immortality. A Northwestern University organic chemist and his team now have developed a promising molecular tool that targets and inhibits one of cell immortality's underlying gears: ...

A tangled web: Teasing out the effects of CBD on canine seizures

Cannabidiol, popularly known as CBD, gained mainstream fame for treating seizures with a strain of hemp called "Charlotte's Web." It was named for Charlotte Figi, a child with Dravet syndrome whose family was so desperate ...

New Cas9 variant makes genome editing even more precise

CRISPR-Cas9 has revolutionized the field of genetics by its ability to cut DNA at defined target sites. Researchers are using the Cas9 enzyme to specifically switch off genes, or insert new DNA fragments into the genome. ...

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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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