The nature of the enzyme
Metabolism is the basis for all living activities of organisms, and metabolism is inseparable from the catalysis of enzymes. Enzymes are catalytically active organisms produced by living cells. In essence, the vast majority of enzymes are proteins, and a few are RNA, ie, ribonucleic acid, a genetic information carrier.
Proteins with enzymatic activity are classified into simple proteins and binding proteins. Simple protein enzymes are composed of amino acids and contain no other substances, such as pepsin. Protein-binding enzymes are composed of simple proteins and cofactors, such as lactate dehydrogenase, transaminase, and the like. The simple protein portion that makes up the enzyme is called the enzyme protein or the main enzyme, and the prosthetic portion is called the coenzymes. The binding enzyme is generally a combination of a primary enzyme and a coenzyme, and becomes a whole enzyme to function as an enzyme. Moreover, the physical and chemical properties of proteins, enzymes generally have, such as being susceptible to external factors such as temperature and pH, high catalytic efficiency, and high specificity.
Role of enzyme
Enzymes can be utilized in many different fields, such asenzymes for research, enzymes for diagnostics, industrial enzyme and enzymes for daily use. Due to the action of the enzyme, the chemical reaction in the organism can be effectively carried out under very mild conditions, enabling the organism to digest food, absorb nutrients, and maintain visceral functions such as anti-inflammatory detoxification, metabolism, immunity, energy production, blood promotion, circulation, etc. The body contains a variety of enzymes that control many metabolic processes such as metabolism, nutrition and bioenergy conversion. Most reactions that are closely related to life processes are enzyme-catalyzed reactions.
The most important role of the enzyme is catalysis. It enables the complex metabolism of substances in cells to be carried out in an orderly manner, adapting the metabolism of substances to normal physiological functions. If the enzyme deficiency or activity is weakened due to genetic defects or other reasons, the catalytic reaction of the enzyme may be abnormal, resulting in disorder of the substance metabolism or even disease.
The catalytic mechanism of the enzyme mainly includes acid-base catalysis and covalent catalysis. Acid-base catalysis refers to the catalytic action of proton transfer to accelerate the reaction. Covalent catalysis means that the substrate or a portion of the substrate forms a covalent bond with the catalyst and is then transferred to the second substrate. Many enzyme-catalyzed group transfer reactions are carried out by covalent catalysis.
There are a large number of enzymes in the human body, which are complex in structure and various in variety. For example, when people chew rice and steamed buns in their mouths, the longer they chew, the sweeter the taste. This is because the starch in rice is hydrolyzed to maltose by the action of salivary amylase secreted by the oral cavity. Therefore, people chewing more when eating can mix food and saliva well, which is good for digestion. In addition, the protein that the human body takes from food must be hydrolyzed into amino acids by various proteolytic enzymes in nutrition industry such as pepsin, and then the specific amino acids are selected by other enzymes to reconstitute the proteins required in a certain order. There are many complex chemical reactions here.
How does the enzyme reduce the activation energy of the reaction?
The catalytic mechanism of the enzyme is to reduce the activation energy of the reaction (from data in enzyme libraries). The chemical reaction can be carried out because a part of the substrate molecules have been activated to become activated molecules, and the more activated molecules, the faster the reaction rate. The enzyme-substrate complex reacts to form a product while releasing the enzyme, which binds to another substrate molecule and increases the rate of chemical reaction by reducing the activation of the reaction. Enzymes can speed up the chemical reaction, but can not change the equilibrium point of the chemical reaction, which means that the enzyme promotes the forward reaction and reverse reaction in the same proportion, so the enzyme's role is to shorten the time required to reach equilibrium.
A biologist and writer lives in New York.