About Ig Heavy Chain Constant Region:
The immunoglobulin heavy chain (IgH) is the large polypeptide subunit of an antibody (immunoglobulin). In the human genome, the IgH gene loci are on chromosome 14.
Ig Heavy Chain Constant Region Function
Typical antibodies are composed of two immunoglobulin (Ig) heavy chains and two Ig light chains. There are several different types of heavy chain that define the class or isotype of an antibody. These heavy chain types can differ between animals.
All heavy chains contain a series of immunoglobulin domains. They typically have one variable domain (VH) that is essential for binding antigen and several constant domains such as CH1, CH2, and so forth. Production of a viable heavy chain is a crucial step in B cell maturation. If the heavy chain can bind to a surrogate light chain and move to the plasma membrane, the developing B cell can produce its own light chain.
However, the heavy chain doesn’t necessarily need to bind to a light chain. Pre-B lymphocytes can synthesize heavy chain without the need for light chain. This allows the heavy chain to bind to a heavy-chain binding protein
Ig Heavy Chain Constant Region Classes
There are five different types of mammalian immunoglobulin heavy chain: γ, δ, α, μ and ε. They define classes of immunoglobulins: IgG, IgD, IgA, IgM and IgE, respectively. Heavy chains α and γ have approximately 450 amino acids, while μ and ε have approximately 550 amino acids.
Ig Heavy Chain Constant Region Regions
Heavy chains have two regions; a constant region and a variable region.
The constant region for heavy chains γ, α and δ have a constant region composed of three tandem immunoglobulin domains. There is also a hinge for flexibility. For heavy chains μ and ε, the constant region is composed of four domains.
Variable regions differ between B cells, but is the same for immunoglobulins produced by the same B cell or B cell clone.