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a collection of objects linked together in linear fashion, or end to end, as the assemblage of atoms or radicals in a chemical compound, or an assemblage of individual bacterial cells.
branched chain an open chain of atoms, usually carbon, with one or more side chains attached to it.
closed chain several atoms linked together so as to form a ring, which may be saturated, as in cyclopentane, or aromatic, as in benzene.
H chain (heavy chain) any of the large polypeptide chains of five classes that, paired with the L or light chains, make up the antibody molecule of an immunoglobulin; heavy chains bear the antigenic determinants that differentiate the classes of immunoglobulins. See also heavy chain disease.
J chain a polypeptide occurring in polymeric IgM and IgA molecules.
L chain (light chain) either of the two small polypeptide chains (molecular weight 22,000) that, when linked to H or heavy chains by disulfide bonds, make up the antibody molecule of an immunoglobulin monomer; they are of two types, kappa and lambda, which are unrelated to immunoglobulin class differences.
open chain a series of atoms united in a straight line; components of this series are related to methane.
chain reaction a chemical reaction that is self-propagating; each time a free radical is destroyed a new one is formed.
side chain a group of atoms attached to a larger chain or to a ring.
a polypeptide chain a subunit of an immunoglobulin molecule, of high molecular weight, such as the γ, α, μ, δ, or ε chains, determining the immunoglobulin class and subclass. This chain also determines whether complement can be bound and whether the chain can pass through the placenta. There are two identical chains in each immunoglobulin.
Synonym(s): H chain
The larger of the two types of polypeptide chains in immunoglobulins, consisting of an antigen-binding portion having a variable amino acid sequence, and a constant region that defines the antibody class.
heav·y chain(hev'ē chān)
A polypeptide chain of high molecular weight determining the class and subclass of an immunoglobulin.