“enzyme”的概念、定义、翻译、参考文献-科学参考

enzyme

Chemistry

A protein that acts as a catalyst in biochemical reactions. Each enzyme is specific to a particular reaction or group of similar reactions. Many require the association of certain nonprotein cofactors in order to function. The molecule undergoing reaction (the substrate) binds to a specific active site on the enzyme molecule to form a short-lived intermediate (see enzyme–substrate complex): this greatly increases (by a factor of up to 10²⁰) the rate at which the reaction proceeds to form the product. Enzyme activity is influenced by substrate concentration and by temperature and pH, which must lie within a certain range. Other molecules may compete for the active site, causing inhibition of the enzyme or even irreversible destruction of its catalytic properties.
Enzyme production is governed by a cell’s genes. Enzyme activity is further controlled by pH changes, alterations in the concentrations of essential cofactors, feedback inhibition by the products of the reaction, and activation by another enzyme, either from a less active form or an inactive precursor (zymogen). Such changes may themselves be under the control of hormones or the nervous system. See also enzyme kinetics.
Enzymes are classified into six major groups, according to the type of reaction they catalyse:
1. (1) oxidoreductases;
2. (2) transferases;
3. (3) hydrolases;
4. (4) lyases;
5. (5) isomerases;
6. (6) ligases.
The names of most individual enzymes also end in -ase, which is added to the names of the substrates on which they act. Thus lactase is the enzyme that acts to break down lactose; it is classified as a hydrolase.
https://www.qmul.ac.uk/sbcs/iubmb/enzyme/ Information about IUPAC nomenclature

Chemical Engineering

A protein molecule that catalyzes biochemical reactions. It has a complex molecular structure and its molecular shape or conformation plays an important role in its function as a catalyst. Enzymes as biocatalysts promote biochemical reactions and involve a substrate molecule, which is converted into products. As with all catalysts, enzymes lower the activation energy of the biochemical reaction and increase the rate of reaction. Every type of enzyme is specific to a particular biochemical reaction. For example, maltose and sucrose are disaccharides but are hydrolyzed by different enzymes, with the former by an enzyme called maltase and the latter by invertase. The molecular structure of the enzyme is complex and, being a protein, is formed from long folded chains of amino acids. The substrate undergoing reaction binds to an active site on the enzyme in a lock and key mechanism to form a short-lived enzyme–substrate complex which dissociates to form the product. Enzyme reactions operate most effectively at a certain optimum temperature and within a narrow pH range. The names of most enzymes end with –ase, such as amylase, which is used to break down starches into simple sugars. Enzymes are denatured with excessive temperature, very low or high pH, and certain chemicals.

Biology

A protein that acts as a catalyst in biochemical reactions. Each enzyme is specific to a particular reaction or group of similar reactions. Many require the association of certain nonprotein cofactors in order to function. The molecule undergoing reaction (the substrate) binds to a specific active site on the enzyme molecule to form a short-lived intermediate (see enzyme-substrate complex): this greatly increases (by a factor of up to 10²⁰) the rate at which the reaction proceeds to form the product. Enzyme activity is influenced by substrate concentration and by temperature and pH, which must lie within a certain range. Other molecules may compete for the active site, causing inhibition of the enzyme or even irreversible destruction of its catalytic properties.
Enzyme production is governed by expression of the particular gene encoding the enzyme. This expression is in turn regulated by mechanisms depending on a host of factors, such as stage of development of the organism, type of tissue, hormonal and nutritional status, nature of the environment, etc. Enzyme activity is further controlled by pH changes, alterations in the concentrations of essential cofactors, feedback inhibition by the products of the reaction, and activation by another enzyme, either from a less active form or an inactive precursor (zymogen). Such changes may themselves be under the control of hormones or the nervous system. See also enzyme kinetics.
Enzymes are classified into six major groups, according to the type of reaction they catalyse: (1) oxidoreductases; (2) transferases; (3) hydrolases; (4) lyases; (5) isomerases; (6) ligases.
The names of most individual enzymes also end in -ase, which is added to the names of the substrates on which they act. Thus lactase is the enzyme that acts to break down lactose; it is classified as a hydrolase.

单词	enzyme
释义	enzyme Chemistry A protein that acts as a catalyst in biochemical reactions. Each enzyme is specific to a particular reaction or group of similar reactions. Many require the association of certain nonprotein cofactors in order to function. The molecule undergoing reaction (the substrate) binds to a specific active site on the enzyme molecule to form a short-lived intermediate (see enzyme–substrate complex): this greatly increases (by a factor of up to 10²⁰) the rate at which the reaction proceeds to form the product. Enzyme activity is influenced by substrate concentration and by temperature and pH, which must lie within a certain range. Other molecules may compete for the active site, causing inhibition of the enzyme or even irreversible destruction of its catalytic properties. Enzyme production is governed by a cell’s genes. Enzyme activity is further controlled by pH changes, alterations in the concentrations of essential cofactors, feedback inhibition by the products of the reaction, and activation by another enzyme, either from a less active form or an inactive precursor (zymogen). Such changes may themselves be under the control of hormones or the nervous system. See also enzyme kinetics. Enzymes are classified into six major groups, according to the type of reaction they catalyse: (1) oxidoreductases; (2) transferases; (3) hydrolases; (4) lyases; (5) isomerases; (6) ligases. The names of most individual enzymes also end in -ase, which is added to the names of the substrates on which they act. Thus lactase is the enzyme that acts to break down lactose; it is classified as a hydrolase. https://www.qmul.ac.uk/sbcs/iubmb/enzyme/ Information about IUPAC nomenclature Chemical Engineering A protein molecule that catalyzes biochemical reactions. It has a complex molecular structure and its molecular shape or conformation plays an important role in its function as a catalyst. Enzymes as biocatalysts promote biochemical reactions and involve a substrate molecule, which is converted into products. As with all catalysts, enzymes lower the activation energy of the biochemical reaction and increase the rate of reaction. Every type of enzyme is specific to a particular biochemical reaction. For example, maltose and sucrose are disaccharides but are hydrolyzed by different enzymes, with the former by an enzyme called maltase and the latter by invertase. The molecular structure of the enzyme is complex and, being a protein, is formed from long folded chains of amino acids. The substrate undergoing reaction binds to an active site on the enzyme in a lock and key mechanism to form a short-lived enzyme–substrate complex which dissociates to form the product. Enzyme reactions operate most effectively at a certain optimum temperature and within a narrow pH range. The names of most enzymes end with –ase, such as amylase, which is used to break down starches into simple sugars. Enzymes are denatured with excessive temperature, very low or high pH, and certain chemicals. Biology A protein that acts as a catalyst in biochemical reactions. Each enzyme is specific to a particular reaction or group of similar reactions. Many require the association of certain nonprotein cofactors in order to function. The molecule undergoing reaction (the substrate) binds to a specific active site on the enzyme molecule to form a short-lived intermediate (see enzyme-substrate complex): this greatly increases (by a factor of up to 10²⁰) the rate at which the reaction proceeds to form the product. Enzyme activity is influenced by substrate concentration and by temperature and pH, which must lie within a certain range. Other molecules may compete for the active site, causing inhibition of the enzyme or even irreversible destruction of its catalytic properties. Enzyme production is governed by expression of the particular gene encoding the enzyme. This expression is in turn regulated by mechanisms depending on a host of factors, such as stage of development of the organism, type of tissue, hormonal and nutritional status, nature of the environment, etc. Enzyme activity is further controlled by pH changes, alterations in the concentrations of essential cofactors, feedback inhibition by the products of the reaction, and activation by another enzyme, either from a less active form or an inactive precursor (zymogen). Such changes may themselves be under the control of hormones or the nervous system. See also enzyme kinetics. Enzymes are classified into six major groups, according to the type of reaction they catalyse: (1) oxidoreductases; (2) transferases; (3) hydrolases; (4) lyases; (5) isomerases; (6) ligases. The names of most individual enzymes also end in -ase, which is added to the names of the substrates on which they act. Thus lactase is the enzyme that acts to break down lactose; it is classified as a hydrolase.
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