Isolation of phosvitin: retention of small molecular weight species and staining characteristics on electrophoretic gels.

Phosvitin was prepared from chicken yolk by a variety of published methods, including a new procedure modified from our own original method. Yolk granules and all phosvitin preparations were found to contain a cluster of phosphoproteins ranging in size from Mr 28,000 to 43,000 when electrophoresed on polyacrylamide gradient gels and stained with Stains-all. However, only the current preparation contained three additional phosphoproteins (Mr 13,000, 15,000, and 18,000) that are also present in yolk granules. None of these components could be demonstrated with Coomassie blue.