Alias of enzyme: enzyme
Enzyme (English: enzyme, from Greek: ε νννυννν, "in yeast") refers to a high molecular substance with biocatalytic function. In the catalytic reaction system of enzyme, the reactant molecule is called substrate, and the substrate is converted into another molecule through the catalysis of enzyme. Almost all cell activities require the participation of enzymes to improve efficiency. Similar to other non-biological catalysts, enzymes can accelerate the reaction rate by reducing the activation energy of chemical reactions (expressed by Ea or δ G), and most enzymes can increase the reaction rate catalyzed by them by millions of times. In fact, enzyme is another way to provide lower activation energy demand, so that more reaction particles can have kinetic energy not less than activation energy, thus accelerating the reaction rate. As a catalyst, the enzyme itself is not consumed in the reaction process, nor does it affect the chemical balance of the reaction. Enzymes have both positive and negative catalytic effects, which can not only accelerate the reaction rate, but also reduce the reaction rate. Different from other non-biological catalysts, enzymes are highly specific and only catalyze specific reactions or produce specific configurations.
Although most enzymes are protein, a few molecules with biocatalytic function are not protein, and some RNA molecules called ribozymes also have catalytic function. In addition, the synthetic so-called artificial enzyme also has catalytic activity similar to that of enzyme, including synthetic DNA. Some people think that enzymes should be defined as biomacromolecules with catalytic function, that is, biocatalysts.
Comparative characteristics
1。 High efficiency: the catalytic efficiency of enzyme is higher than that of inorganic catalyst, which makes the reaction speed faster;
2。 Specificity: An enzyme can only catalyze one or one substrate, such as protease can only catalyze the hydrolysis of protein into polypeptide.
3。 Diversity: There are many kinds of enzymes. So far, more than 4000 kinds of enzymes have been found, and the number of enzymes in organisms is far greater than this.
4。 Mildness: chemical reactions catalyzed by enzymes are generally carried out under mild conditions.
5。 Activity adjustability: including inhibitor and activator regulation, feedback inhibition regulation, valence modification regulation and allosteric regulation.
6。 Variability: most enzymes are protein, so they will be destroyed by high temperature, strong acid and strong alkali;
7。 The catalysis of some enzymes is related to cofactors.