Protein cross-linking by self-assisted intermolecular disulfide bond formation.

Storage of proteins is a physiological means to provide a reservoir for regulated utilization by the organism. Examples are the intracellular storage of exportable proteins in secretion granules, e.g., in exocrine glands, and the extracellular deposition of secretory proteins, e.g., of thyroglobulin (TG) in the lumina of thyroid follicles. In all cases, tight packaging of protein molecules is observed, which is usually reached by intense intermolecular interactions. One mechanism that results in these interactions and is presumably common to many storage proteins is the formation of intermolecular disulfide bonds.