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 are the antigen recognition molecules of B cells. An Immunoglobulins 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 chains, there is one variable region and a constant region. The variable region is the most important for binding to antigens.