LCN1 is a member of the lipocalin family of small secretory proteins. Lipocalins are extracellular transport proteins that bind to a variety of hydrophobic ligands. This protein is the primary lipid binding protein in tears and is overproduced in response to multiple stimuli including infection and stress. It may be a marker for chromosome aneuploidy as well as an autoantigen in Sjogren's syndrome. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene, and two pseudogenes of this gene are also located on the long arm of chromosome 9. Recombinant human LCN1 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.