Salivary protein that stabilizes saliva supersaturated with calcium salts by inhibiting the precipitation of calcium phosphate salts. It also modulates hydroxyapatite crystal formation on the tooth surface. Both isoforms can occur with the Phe-62 deletion. Secreted by parotid and submandibular glands. Substrate for transglutaminase-2. More than 95% of the cyclized peptide is cyclo-statherin Q-37, and less than 5% is cyclo-statherin Q-39. Cyclized forms account for about 1% of total statherin in saliva. Sulfated on tyrosine residues. With phosphorylated Ser-21 and Ser-22. With phosphorylated Ser-21 and Ser-22 and transglutamine cross-link. Belongs to the histatin/statherin family.