Antibodies (immunoglobulines, Ig) are special protein molecules, which are produced by B-lymphocytes. They bond selectively with certain atomic groups on surfaces of xenogenic organisms or toxic molecules, produced by them.
ANTIBODIES
Antibodies (immunoglobulines, Ig) are special protein molecules, which are produced by B-lymphocytes. They bond selectively with certain atomic groups on surfaces of xenogenic organisms or toxic molecules, produced by them.
Huge variety of antibodies is created by accidental changes in DNA, which encodes the unique antigen-binding site. The most simple molecules of antibodies have Y-form with two identical antigen-binding sites, one on the end of each of the two "branches". A molecule of an antibody consists of four polypeptide chains: two identical light chains (L-chains, 220 amino acids length each) and two identical heavy chains (H-chains, 220 amino acids length each). All four chains are joined among each other by noncovalent interactions and covalent bonds (disulfide bridges).
There are 5 different classes of antibodies in superior vertebrates - IgA, IgD, IgE, IgG, IgM. Each of them has iys own subclass of heavy chains (α, δ, ε, γ, μ). There are a number of subclasses IgG and some other immunoglobulines.