Egg Proteins of Coho Salmon (Oncorhynchus kisutch): Chromatographic Separation and Molecular Weights of the Major Proteins in the High Density Fraction and their Presence in Salmon Plasma

The molecular weights of the three major proteins in the soluble fraction of coho salmon (Oncorhynchus kisutch) eggs were found to be: lipovitellin, 390,000; β′-component, 30,000; and phosvitin, 27,000. Immunological techniques showed that these proteins were present in the plasma of sexually maturing female coho and of estrogenized prepuberal coho of both sexes but not of sexually maturing males or nonestrogenized prepuberal coho. These findings support the previous postulation that the β′-component should be classified not as a livetin but as an egg protein, as are lipovitellin and phosvitin.