The basic concept of Ig is an active globulin that can specifically bind to it
Antigens are substances, such as bacteria, viruses or their metabolites, that can produce a series of immune responses.
Antibody has the ability to resist infectious diseases. It is a kind of specific substance, such as immunoglobulin, which combines with the antigen and stimulates the body to produce after the antigen enters the human body
Classification: homotype:
It refers to the antigen-specific marker shared by immunoglobulin (Ig) molecules of all normal individuals of the same genus
Allotype
Different individuals of the same genus, such as IgG and IgA
Unique type
It refers to the antigen-specific markers of immunoglobulin molecule V region and surface antigen (recognition) receptor V region of T and B cells produced by different B cell clones.
Basic composition of IgG
1. Heavy chain (440 aa residues)
Constant area and variable area
2. Light chain (214 aa residues)
Constant area and variable area
Basic properties of LF
（1） Basic structure and composition of LF
Color: red;
Composition: Fe3 +, mannose, galactose, acetylglucosamine, sialic acid.
Basic properties of LZ
Property: basic globulin
Thermal stability: high, disulfide bond
Isoelectric point: ph10.7 ~ 11.0
Structure: LZ and α - lactalbumin of human milk have 74% of the same primary structure.
Processing adaptability of LZ
（1） Thermal stability
1. Acid alkali environment
Acid condition: stable
Alkaline conditions: unstable
2. Salt solution
Low concentration: the activation of LZ is related to the ionic strength;
High concentration: LZ was inhibited, the higher the cation concentration, the stronger the inhibition.
3、 Application of LZ in food
1. Food preservation
preservative
2. Production of dairy products such as cheese
Shorten the time of CaCl2 coagulation
