ISOLATION AND COMPOSITION OF AVIAN EGG YOLK GRANULES AND THEIR CONSTITUENT α- AND β-LIPOVITELLINS

Publisher Website
Google Scholar
Abstract
The yolk granules from hen''s egg represent on a dry basis 23% of the yolk solids, and they contain about 90% of the protein phosphorus, 95%, of the iron, and nearly 70% of the calcium in yolk. Ultracentrifugal and other analyses on solutions of the granules show that they are 70% [alpha]- and [beta]-lipovitellin in an approximate ratio of 11.8, 16% phosvitin, and 12% low-density lipo-protein. The properties and composition of the two lipovitellins isolated from the granules are the same as those isolated from solutions of whole yolk. Further purification reduces the protein phosphorus in [alpha]-lipo-vitellin to 0.50% and in [beta]-lipovitellin to 0.27, and this confirms that [alpha]-vitellin has a higher phosphorus content. Experiments at low temperature suggest that phosvitin exists in the granules as a high molecular weight complex.