The old name for enzymes. With special catalytic ability of the protein. It consists of organisms (animal, plant, microorganism), or enzyme as a biological catalyst. It continues to promote a large number of complex chemical reactions in living organisms. Such as amylase starch and glycogen hydrolysis catalyst into dextrin and maltose; enzymatic protein hydrolysis peptide; lipase catalyzed hydrolysis of fats into fatty acids and glycerol.
Analysis of organic reagent is determined for inorganic elements in the separation and analysis of precipitant for enrichment, extraction agent, chelating agent and indicator for organic compounds, and not to refer to the general solvent, organic acid and organic alkali. These organic reagents must have good sensitivity and selectivity. With the development of analytical chemistry and the chemical industry, will be developed this kind of reagent sensitivity and better selectivity, such as since 1967 for some metal (such as alkali metal, alkaline earth metal) crown ether compounds and ammonium ion complexing is such.