Phosvitin,a phosphoprotein known as an iron-carrier in egg yolk,binds almost all the yolk iron.

Phosvitin is precursor of the major egg-yolk proteins that are sources of nutrients during early development of oviparous organisms.Phosvitin is believed to be of importance in sequestering calcium, iron and other cations for the developing embryo.

Phosvitin, a highly phosphorylated glycoprotein, represents the major fraction of hen egg yolk phosphoproteins.The secondary structure of phosvitin is observed to be sensitive to environmental factors as previously reported although the present studies differ in some respects from earlier results. Preliminary results suggest that Ca2+ ions trigger a decrease in beta-sheet structure at pH 2.