Sialoglycoproteins from the eggs of Pacific herring. Isolation and characterization.

A family of hitherto undescribed sialoglycoproteins has been isolated from the eggs of Pacific herring in a yield about 10 times as much as phosvitin known as a major protein component of the eggs. The sialoglycoproteins are composed of 60-50% of carbohydrates and 40-50% of protein. The carbohydrate composition is similar to that of glycoproteins known to have complex types of heterosaccharide units whereas the amino acid composition is unique. The molecular weights ranging over 8800-13000 were determined for the sialoglycoprotein fractions by sedimentation equilibrium. The low mobility of the sialoglycoproteins during sodium dodecyl sulfate gel electrophoresis is discussed in terms of low values of hydrophobicity.