IONIC-STRENGTH AND PH EFFECTS ON COMPOSITION AND MICROSTRUCTURE OF YOLK GRANULES

We investigated the microstructure of hen egg granules. Polyacrylamide gel electrophoresis revealed that the granules consisted of three proteins (low-density lipoprotein, lipovitellin and phosvitin). Atomic absorption spectrometry revealed a notable amount of divalent and trivalent cations. Scanning electron microscopy showed that pH modifications induced the loss of granule structure by solubilization of proteins. Similar observations were made when ionic strength was increased by addition of sodium chloride. All results were indicative of the existence of phosphocalcic bridges between phosphate groups of the three proteins.