Immunoglobulin light chain variable region fragment [Homo sapiens] is a fragment (Phe-Thr-Leu-Lys-Ile-Ser-Arg) on the variable region of the human immunoglobulin light chain.
Immunoglobulins (Ig) are the antigen recognition molecules of B cells. An Ig molecule is made up of 2 identical heavy chains and 2 identical light chains joined by disulfide bonds so that each heavy chain is linked to a light chain and the 2 heavy chains are linked together. On each of the light chain, there is one variable region and a constant region. The variable region is the most important for binding to antigens.
The antigen combining site of an antibody is made up of the variable regions of one light chain and one heavy chain. Within the variable regions, typically comprising 105-110 amino acids, some positions show more sequence variation than others. The variable fragments are the smallest fragment made from enzymatic cleavage of IgG and IgM class antibodies.
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