Important role in the capacity of milk to transport calcium phosphate. Casoxin D acts as opioid antagonist and has vasorelaxing activity mediated by bradykinin B1 receptors. Heteromultimers of alpha-s1 casein and kappa-casein; disulfide-linked. Mammary gland specific. Secreted in milk. Not glycosylated. In milk, the alpha s1- and beta-caseins precipitate in presence of calcium (so-called calcium-sensitive caseins). Kappa-casein prevents the precipitation of the other caseins by calcium through the formation of large stable colloidal particles termed micelles. Belongs to the alpha-casein family. Of buttons, digestion and glue - Issue 16 of November 2001