Proteins and lipoproteins in yolk from eggs of the estuarine crocodile ( Crocodylus porosus); A comparison with egg yolk of the hen ( Gallus domesticus)

Abstract

1. 1. The livetin patterns of the two species Crocodylus porosus and Gallus domesticus were very different and it was difficult to find a correspondence. 2. 2. In C. porosus the granules were a larger proportion of the total yolk but they contained very little low-density lipoprotein when compared with granules from hens' eggs. 3. 3. The low-density lipoprotein was a lower proportion of the yolk of C. porosus: 30% of the dry weight compared with 60% for the hen. Furthermore, the former apparently contained an unstable fraction consisting of large particles. 4. 4. The apoprotein patterns of the low-density lipoprotein of C. porosus eggs had a higher proportion of high-molecular weight constituents than that of the hen. 5. 5. A glycoprotein with M r, approximately 2 × 10 4 has been isolated that does not correspond to a known avian protein. 6. 6. The characteristic protein of avian egg yolk, apovitellenin I, if present, was a minor constituent.