Formation of complexes between lecithin and apovitellenin I, an avian egg-yolk apoprotein

In a study of lipid-protein interactions in egg yolk, it was found that L-alpha-dipalmitoyl lecithin gave two distinct noncovalent complexes (A and B) with apovitellenin I, an apoprotein in the major yolk lipoprotein. Interaction took place under widely varied conditions, and yolk lecithin gave similar complexes. Complex A, which was formed within minutes, consisted of round particles of about 9 nm diameter. Complex B, which was formed more slowly, consisted of larger particles, possibly resembling curved discs, with diameter of 30-40 nm. The preparation and some properties of these complexes are described. It is suggested that they may be suitable for an extensive study of phospholipid-protein interactions in yolk.