A heavy chain is the large polypeptide subunit of a protein complex, such as a motor protein (e.g. myosin, kinesin, or dynein) or antibody (or immunoglobulin).
It commonly refers to the immunoglobulin heavy chain. The heavy (H) chain is the larger of the two types of chains that comprise a normal immunoglobulin or antibody molecule. The heavy chain portion of an antibody contains 2 regions; the Fab (Antigen-binding portion) and Fc (Constant region; confers biological activity such as phagocytosis of microorganisms, lysis, and clumping of organisms together). Amino Acid sequence determines the type of heavy chains and heavy chains define the isotype of Ig. Immunoglobulin G has gamma heavy chains, IgA has α alpha heavy chains, IgM has μ mu heavy chains, IgD has δ delta heavy chains, and IgE has ε epsilon heavy chains. In contrast, all light chains are either κ kappa or λ lambda light chains, either of which may be found on any Ig molecule, regardless of isotype. Each Ig unit is made up of 2 heavy chains, 2 light chains, and has 2 antigen-binding sites. Heavy Chain is joined with the light chain with the help of di-sulphur bonds.
Famous quotes containing the words heavy and/or chain:
“Our sense of these things changes and they change,
Not as in metaphor, but in our sense
Of them. So sense exceeds all metaphor.
It exceeds the heavy changes of the light.
It is like a flow of meanings with no speech
And of as many meanings as of men.”
—Wallace Stevens (1879–1955)
“By this unprincipled facility of changing the state as often, and as much, and in as many ways as there are floating fancies or fashions, the whole chain and continuity of the commonwealth would be broken. No one generation could link with the other. Men would become little better than the flies of a summer.”
—Edmund Burke (1729–1797)