Glycosidases
| Glycosidases | ||
|---|---|---|
| Enzyme classification | ||
| EC, category | 3.2.1. , Hydrolases | |
| Response type | hydrolysis | |
| Substrate | Glycosides | |
Glycosidases (EC 3.2.1.), Also glycosidases , belong to the enzyme class of hydrolases . Glycosidases are ubiquitously occurring enzymes , which in all kingdoms (plants, animals, fungi and protists ) can be found.
A glycosidase reversibly catalyzes the hydrolysis of a glycosidic bond in a glycoside , releasing a sugar ("glycon") and the so-called "aglycon" by consuming a water molecule. They are usually more or less specific for the sugar to be split off, whereas the type of aglycone plays a lesser role. Since the equilibrium of the reaction is on the part of the cleavage products, no energy supply is necessary. Under special laboratory conditions , this equilibrium reaction can also be used to synthesize glycosides that are difficult to obtain synthetically.
Glycosidases are common digestive enzymes. Such glycosidases are rather unspecific, so they can hydrolyze a wide range of glycosides. In addition to their role as energy carriers, carbohydrates also play a role in biochemical signaling processes such as B. communication between cells plays an important role. When complex carbohydrate structures are built up on the cell surface, individual monosaccharides are split off again in intermediate steps by very specific glycosidases. For example, there are the amylases , lysozyme , galactosidases , mannosidases , fucosidases , cellulases and many other glycosidases.
Glycosides are built up by mostly very specific glycosyltransferases with the addition of energy.
The pH optimum of glycosidases for insects of various orders is between pH 4.0 and pH 7.0. In many plants, however, the optimum pH is only in the acidic range around pH 5.0.