As a general classification, enzymes are divided into "catabolic enzymes" and "synthetic enzymes". For example, breaking down proteins into amino acids of the same size that can be absorbed, and synthesizing the necessary proteins for the body through the enzymes of the decomposition system and the absorbed amino acids, all of which are carried out according to the enzymes. However, in order to distinguish the enzymes used inside and outside the living body, enzymes used in living tissues are referred to as "metabolic enzymes", and enzymes used outside living tissues such as the gastrointestinal tract are referred to as "digestive enzymes", which can also be said to be for convenience. In biochemistry, it can be divided into six categories: oxidoreductases, transferases, hydrolases, lyases, isomerases, and synthetases.
According to the different reaction properties catalyzed by enzymes, they can be divided into six categories: ① Oxidoreductases are enzymes that promote substrate redox reactions, which are a type of enzyme that catalyzes redox reactions and can be divided into two categories: oxidase and reductase; ② Transferases are enzymes that catalyze the transfer or exchange of certain functional groups (such as acetyl, methyl, amino, phosphate, etc.) between substrates, such as methyltransferases, aminotransferases, acetyltransferases, sulfidases, kinases, and polymerases Hydrolases are enzymes that catalyze the hydrolysis reaction of substrates, such as amylase, protease, lipase, phosphatase, glycosidase, Staphylococcus aureus, and lysozyme Lyases catalyze the reaction or reverse reaction of removing a functional group from a substrate (non hydrolytic) and leaving a double bond, such as dehydratase, decarboxylase, carbonic anhydrase, aldolase, citrate synthase, etc. Many Lyases catalyze reverse reactions, forming a new chemical bond between two substrates and eliminating a double bond of one substrate. Synthases belong to this class; ⑤ Isomerases are enzymes that catalyze the conversion of various isomers, geometric isomers, or optical isomers into each other, such as isomerases, surface isomerases, racemases, etc Ligases catalyze the synthesis of two substrates into a single molecule compound, while also coupling with enzymes that release energy through ATP phosphate bond cleavage. For example, glutamine synthase, DNA ligase, amino acid: tRNA ligase, and biotin dependent carboxylase.
According to the amino acid composition of proteases, they can be divided into four categories: ① Serine proteases, which are effective enzymes with broad catalytic activity and can be obtained in tissues when needed, with chymotrypsin, trypsin, fibrinogen activator, and leukocyte elastase being the most famous; ② Cysteine protease and papain are undoubtedly the most famous and well studied members of this group; ③ Aspartase has many well-known enzymes, such as renin and pepsin; ④ Metalloproteinase is widely known in the field of wound healing due to its ability to decompose collagen and other extracellular matrix components.