More than 40 years into the HIV pandemic, scientists are still turning up clues revealing how the virus hijacks its host's cellular processes to support its own replication—and promote the long-term survival of the virus ...
Synapses are small gaps between neurons through which signals are transmitted. This transmission of signals is what allows neurons to communicate and ultimately produce complex internal processes, such as thoughts and feelings, ...
Research led by Peking University, China, has looked into gut microbiota production of isozymes, which do similar work to human enzymes but have different structures.
In a new breakthrough to understand more about the mammalian brain, University of Copenhagen researchers have made an incredible discovery. Namely, a vital enzyme that enables brain signals is switching on and off at random, ...
Nov 23, 2022
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A large team of researchers from Denali Therapeutics, working with colleagues from multiple entities in the U.S. and one in Canada, has found that a LRRK2 inhibitor called DNL201 showed no ill effects to volunteers in a clinical ...
Inside cells, where DNA is packed tightly in the nucleus and rigid proteins keep intricate transport systems on track, some molecules have a simpler way of establishing order. They can self-organize, find one another in crowded ...
Aug 15, 2018
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(Medical Xpress)—Apes, including humans, lack an enzyme called uricase that breaks down uric acid. Because we lack uricase, we are predisposed to developing gout. After reconstructing ancient versions of the enzyme found ...
A little bit of learned fear is a good thing, keeping us from making risky, stupid decisions or falling over and over again into the same trap. But new research from neuroscientists and molecular biologists at USC shows that ...
Jul 15, 2013
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In a new paper released today in Nature, BioFrontiers Institute scientists at the University of Colorado Boulder, Tom Cech and Leslie Leinwand, detailed a new target for anti-cancer drug development that is sitting at the ...
Oct 24, 2012
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A team of Weizmann Institute scientists has turned the tables on an autoimmune disease. In such diseases, including Crohn's and rheumatoid arthritis, the immune system mistakenly attacks the body's tissues. But the scientists ...
Dec 25, 2011
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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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