>Enzyme / Enzymes
Enzyme / Enzymes
Sino Biological provides a range of products (recombinant proteins, antibodies, ELISA kits, gene cDNA clones) for study of enzymes, including proteases, protein kinases, phosphatases, enzymes in carbohydrate metabolism, enzymes in lipid metabolism, and many other enzymes.
Enzyme Products Index
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, enzymes bind temporarily to one or more reactants, called substrates, and convert them into products. Enzymes lower the amount of activation energy needed and thus speed up the reaction. Almost all processes in a biological cell need enzymes to occur at significant rates. Enzymes serve a wide variety of functions inside living organisms. They are indispensable for signal transduction, often via kinases and phosphatases. Several enzymes can work together in a specific order, creating metabolic pathways. In order to function, an enzyme must unite with at least one of the reactants. Most of these interactions are weak and especially, so successful binding of enzyme and substrate requires that the enzyme and its substrate be able to approach each other closely over a fairly broad surface. Thus the analogy that a substrate molecule binds its enzyme likes a key in a lock.
Many enzymes require additional non-protein molecules called cofactors to be bound for activity. Enzyme cofactors can be either inorganic (e.g., metal ions and iron-sulfur clusters) or organic compounds (e.g., flavin and heme). Some enzyme cofactors are small organic molecules called coenzymes. Coenzymes include NADH, NADPH and adenosine triphosphate. Enzyme reaction rates can be decreased by various types of enzyme inhibitors. In competitive inhibition, the inhibitor and substrate compete for the enzyme. Often competitive inhibitors strongly resemble the real substrate of the enzyme. In competitive inhibition the maximal velocity of the reaction is not changed, but higher substrate concentrations are required to reach a given velocity. Non-competitive inhibitors can bind to the enzyme at the same time as the substrate. In contrast to competitive inhibition, the Km stays the same, while the maximal velocity of the reaction (Vmax) is changed. The activity of enzymes is strongly affected by changes in pH and temperature. Each enzyme works best at a certain pH and temperature, its activity decreasing at values above and below that point.