The chemical essence of enzymes is protein or RNA, so they also have primary, secondary, tertiary and even quaternary structures. According to the different molecular composition, it can be divided into simple enzymes and binding enzymes. Only those containing protein are called simple enzymes; Binding enzyme consists of enzyme protein and cofactor.

For example, most hydrolases consist only of protein; Flavin mononucleotide enzyme consists of enzyme protein and cofactor. The protein part of the enzyme protein and the non-protein part of the cofactor in the combined enzyme have catalytic activity only if they are combined into a complete enzyme.

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Enzyme is a biocatalyst, which dominates many catalytic processes such as metabolism, nutrition and energy conversion. Most of the reactions closely related to life processes are enzyme-catalyzed reactions.

These properties of enzymes make the complex metabolic process of substances in cells proceed in an orderly manner, and make the metabolism of substances adapt to normal physiological functions. If an enzyme is defective due to gene defect, or its activity is weakened due to other reasons, it will lead to abnormal reaction catalyzed by the enzyme, disorder of substance metabolism and even disease, so the relationship between enzyme and drug is very close.

Enzymes digest and absorb food eaten by human body, and maintain all functions of internal organs, including cell repair, anti-inflammation, detoxification, metabolism, improving immunity, generating energy and promoting blood circulation.

For example, when rice is chewed in the mouth, the longer the chewing time, the more obvious the sweetness, because the starch in rice is hydrolyzed into maltose under the action of salivary amylase secreted by the mouth. Therefore, chewing more when eating can make food and saliva fully mixed, which is beneficial to digestion.

In addition, there are many hydrolases such as pepsin and trypsin in human body. Protein ingested by human body from food must be hydrolyzed into amino acids under the action of enzymes such as pepsin, and then more than 20 kinds of amino acids needed by human body are selected and recombined into various protein needed by human body in a certain order.

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