News tagged with enzyme
Related topics: protein , cells , bacteria , chemical reactions , cancer
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 and is available under the GNU Free Documentation License.
A DNA variant near a digestive enzyme does not only affect risk of developing diabetes but also affects the response to treatment, an international consortium of researchers including the University of Dundee has found.
Diabetes May 17, 2013 | not rated yet | 0 |
A new study from the University of Cincinnati has found that, when delivered via ultrasound, the natural enzyme plasmin is more effective at dissolving stroke-causing clots than the standard of care, recombinant tissue plasminogen ...
Cardiology May 15, 2013 | not rated yet | 0 |
Researchers at UT Southwestern Medical Center have found that alternative splicing – a process that allows a single gene to code for multiple proteins – appears to be a new potential target for anti-telomerase ...
Cancer Apr 19, 2013 | 5 / 5 (4) | 0 |
Scientists have devised a method for delivering tumor cell-killing enzymes in a way that protects the enzyme until it can do its work inside the cell. In their study in mBio, the online open-access journal of the American Societ ...
Cancer Apr 30, 2013 | not rated yet | 0
A gas associated with the smell of rotten eggs has proven to effectively reduce joint swelling, in research which could lead to advances in the treatment of arthritis.
Arthritis & Rheumatism Apr 29, 2013 | not rated yet | 0
Blocking certain enzymes in the cell may prevent cancer cell division and growth, according to new findings from researchers at the Graduate School of Biomedical Sciences at the Icahn School of Medicine at Mount Sinai. The ...
Cancer Apr 25, 2013 | 5 / 5 (1) | 1
Four years ago, Janelly Martinez-Amador was confined to a bed, unable to move even an arm or lift her head. At age 3, the fragile toddler had the gross motor skills of a newborn and a ventilator kept her ...
Diseases, Conditions, Syndromes Apr 24, 2013 | not rated yet | 0
A study presented today at the International Liver Congress 2013 – which evaluated the relationship between non-alcoholic fatty liver disease (NAFLD), early predictors of atherosclerosis and the 10-year Framingham risk ...
Diseases, Conditions, Syndromes Apr 26, 2013 | not rated yet | 0