There are amino groups and carboxyl groups in protein molecules

　　Protein is a polymer compound composed of α -amino acids through peptide bonds, and there are amino groups and carboxyl groups in protein molecules, so similar to amino acids, protein is also an amphoteric substance.understand recombinant proteins In order to better serve customers and reflect the core competitiveness of products. https://www.alphalifetech.com/

　　(1) Hydrolysis reaction

　　Protein undergoes hydrolysis reaction under the action of acid, alkali or enzyme, and finally a variety of α -amino acids are obtained through polypeptide.

　　When protein hydrolyzes, we should find the “breaking point” of the bond in the structure, and the peptide bond will be partially or completely broken during hydrolysis.

　　(2) Colloidal properties

　　Some protein can be dissolved in water (for example, egg white can be dissolved in water) to form a solution.

　　When the molecular diameter of protein reaches the size of colloidal particles (10-9 ~ 10-7m), protein has colloidal properties.

　　(3) precipitation

　　Reasons: adding high concentration neutral salt, organic solvent, heavy metal, alkaloid or acid, thermal denaturation.

　　A small amount of salt (such as ammonium sulfate, sodium sulfate, etc.) can promote the dissolution of protein. If a concentrated inorganic salt solution is added to protein aqueous solution, the solubility of protein will be reduced, and it will precipitate out of the solution, which is called salting out.

　　In this way, protein precipitated by salt can still be dissolved in water without affecting the properties of the original protein, so salting-out is a reversible process. Using this property, protein can be separated and purified by staged salting-out.

　　(4) degeneration

　　Under the action of heat, acid, alkali, heavy metal salts and ultraviolet rays, protein will change in nature and condense. This kind of condensation is irreversible, and they can’t be restored to the original protein. This change in protein is called transsexuality. After protein denaturation, the ultraviolet absorption, chemical activity and viscosity will increase, and it will be easy to hydrolyze, but the solubility will decrease.

　　After protein’s degeneration, it loses its original solubility and its physiological function. Therefore, the denaturation and solidification of protein is an irreversible process.