Homodimer. Expressed in liver and in sublingual and submaxillary salivary glands. Highly concentrated in secretory fluid such as saliva and urine as well as in hair dandruff extract. Several N-terminal ends may be due to cleavage by signal peptidase at different sites or may be generated by proteolytic processing of the secreted protein. Analysis of the sugar composition shows the presence of GalNAc, Gal, NeuAc, GlcNAc, and Man. May be also O-glycosylated. Causes an allergic reaction in human. Potent allergen responsible for about 80% of anti-horse IgE antibody response in patients who are chronically exposed to horse allergens. Belongs to the calycin superfamily. Lipocalin family.