Enzyme
hideEnzymes 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).
For more information about Enzyme, read the full article at
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News tagged with enzyme
Microbes to Take Over Ethanol Production?
Nov 20, 2009 |
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(PhysOrg.com) -- Not too long ago, it seemed that ethanol production was the wave of the future. The use of trash, wood chips or different types of plants -- usually grass or corn -- to make ethanol was considered ...
Tiny particles can deliver antioxidant enzyme to injured heart cells
Nov 16, 2009 |
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Researchers at Emory University and the Georgia Institute of Technology have developed microscopic polymer beads that can deliver an antioxidant enzyme made naturally by the body into the heart.
Research reveals lipids' unexpected role in triggering death of brain cells
Nov 12, 2009 |
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The lipid that accumulates in brain cells of individuals with an inherited enzyme disorder also drives the cell death that is a hallmark of the disease, according to new research led by St. Jude Children's Research Hospital ...
Novel mouse gene reduces major pathologies associated with Alzheimer's disease
Medicine & Health / Neuroscience
Nov 11, 2009 |
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A new study reveals that a previously undiscovered mouse gene reduces the two major pathological perturbations commonly associated with Alzheimer's disease (AD). The research, published by Cell Press in the November 12 issue ...
Scientists successfully reprogram blood cells
Nov 09, 2009 |
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Researchers have transplanted genetically modified hematopoietic stem cells into mice so that their developing red blood cells produce a critical lysosomal enzyme -preventing or reducing organ and central nervous system damage ...
New discoveries in the yeast Saccharomyces cerevisiae
Nov 04, 2009 |
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Researchers at UAB in collaboration with the University of Stellenbosch, South Africa, have discovered the structure of the PPC descarboxilase (PPCDC) enzyme present in the yeast Saccharomyces cerevisiae, a very important ...
Researchers reconstitute enzyme that synthesizes cholesterol drug lovastatin
Nov 03, 2009 |
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Researchers from the UCLA Henry Samueli School of Engineering and Applied Science have for the first time successfully reconstituted in the laboratory the enzyme responsible for producing the blockbuster cholesterol-lowering ...
Common Pain Relievers May Dilute Power of Flu Shots
Medicine & Health / Medications
Nov 03, 2009 |
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(PhysOrg.com) -- With flu vaccination season in full swing, research from the University of Rochester Medical Center cautions that use of many common pain killers - Advil, Tylenol, aspirin - at the time of injection may blunt ...
Spinal cord regeneration enabled by stabilizing, improving delivery of scar-degrading enzyme
Nov 02, 2009 |
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Researchers have developed an improved version of an enzyme that degrades the dense scar tissue that forms when the central nervous system is damaged. By digesting the tissue that blocks re-growth of damaged ...
JAX publishes online tool for exploring autoimmune disease gene networks
Oct 29, 2009 |
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Currently, 5-8% of the U.S. population is afflicted with an autoimmune disease. Many of these are chronic and require life-long care. Moreover, different autoimmune diseases aggregate within a single family, ...
Venomous bite: Harmless digestive enzyme evolved into venom in two species
Oct 29, 2009 |
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(PhysOrg.com) -- Biologists have shown that independent but similar molecular changes turned a harmless digestive enzyme into a toxin in two unrelated species -- a shrew and a lizard -- giving each a venomous ...
Examining genetic variations among the Huichol population of Mexico
Oct 26, 2009 |
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Mexican researchers examined the polymorphisms of three enzymes -- alcohol dehydrogenase (ADH1B), aldehyde dehydrogenase (ALDH2) and cytochrome P4502E1 (CYP2E1) -- in the Mestizo and Huichol groups.The Huichols, an indigenous ...
Inventive approach may improve enzyme replacement therapy for Fabry disease
Oct 22, 2009 |
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A new study uses a creative structure-based remodeling strategy to design a therapeutic protein that exhibits significant advantages over currently available treatments for a rare disease that often leads to cardiac and renal ...
New artificial enzyme safer for nature
Oct 22, 2009 |
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Perilous and polluting industrial processes can be made safer with enzymes. But only a short range of enzymes have been available for the chemical industry.
Biochemical 'On-Switch' Could Solve Protein Purification Challenge
Oct 20, 2009 |
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(PhysOrg.com) -- Drugs based on engineered proteins represent a new frontier for pharmaceutical makers. Even after they discover a protein that may form the basis of the next wonder drug, however, they have ...
