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An example of crucial esterase is acetylcholine esterase, which assists in transforming the neuron impulse into the acetate group after the hydrolase breaks the acetylcholine into choline and acetic acid. [1] Acetic acid is an important metabolite in the body and a critical intermediate for other reactions such as glycolysis.
An example of a coupled reaction is the phosphorylation of fructose-6-phosphate to form the intermediate fructose-1,6-bisphosphate by the enzyme phosphofructokinase accompanied by the hydrolysis of ATP in the pathway of glycolysis. The resulting chemical reaction within the metabolic pathway is highly thermodynamically favorable and, as a ...
An illustrative example is the effect of catalysts to speed the decomposition of hydrogen peroxide into water and oxygen: . 2 H 2 O 2 → 2 H 2 O + O 2. This reaction proceeds because the reaction products are more stable than the starting compound, but this decomposition is so slow that hydrogen peroxide solutions are commercially available.
An example of an enzyme that contains a cofactor is carbonic anhydrase, which uses a zinc cofactor bound as part of its active site. [61] These tightly bound ions or molecules are usually found in the active site and are involved in catalysis. [1]: 8.1.1 For example, flavin and heme cofactors are often involved in redox reactions. [1]: 17
Using an external PC has some downsides. For example, external PCs typically complicate reaction design because the PC may react with both the bound and unbound substrate. If a reaction occurs between the unbound substrate and the PC, enantioselectivity is lost and other side reactions may occur.
Enzyme catalysis is the increase in the rate of a process by an "enzyme", a biological molecule. Most enzymes are proteins, and most such processes are chemical reactions. Within the enzyme, generally catalysis occurs at a localized site, called the active site.
Catalysts: these may be for example metal ions or coenzymes and they catalyze a reaction by increasing the rate of the reaction and lowering the activation energy. In the simplest sense, the reactions that occur in biosynthesis have the following format: [ 2 ]
In this context, simple organic acids have been used as catalyst for the modification of cellulose in water on multi-ton scale. [9] When the organocatalyst is chiral an avenue is opened to asymmetric catalysis; for example, the use of proline in aldol reactions is an example of chirality and green chemistry. [10]