Proteins of the albumen and vitelline membrane of eggs of the estuarine crocodile, Crocodylus porosus

• Published in: Comparative biochemistry and physiology. B, Comparative biochemistry Vol. 88; no. 3; pp. 863 - 867
• Main Authors: Burley, R.W., Back, J.F., Wellington, J.E., Grigg, G.C.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 1987; Elsevier Science
• Subjects: Biological and medical sciences; Brackish; Crocodylus porosus; Embryology: invertebrates and vertebrates. Teratology; Fundamental and applied biological sciences. Psychology; General aspects. Development. Fetal membranes; Proteins; Embryonic development; Vertebrata; Crocodylus porosus; Egg; Gel electrophoresis; HPLC chromatography; Reptilia; Chemical composition; Crocodilia; Metabolism
• ISSN: 0305-0491
• DOI: 10.1016/0305-0491(87)90256-2

1. 1. In gross composition, the eggs of the estuarine crocodile ( Crocodylus porosus) are similar to those of the hen ( Gallus domesticus). 2. 2. The albumen of C. porosus eggs has a lower proportion of solids than that of the hen (3.6% compared with 12%), the predominant solid being a glycoprotein which is 80% of the total protein. In amino acid composition and properties this protein is similar to avian ovomucin. 3. 3. The main albumen proteins in avian eggs (ovalbumin, ovotransferrin) were not detected in eggs of C. porosus by electrophoresis or chromatography. Instead, a new protein, with mol. wt 5.9 x 10 4, has been isolated from C. porosus albumen. In its amino acid composition this protein differs from known albumen proteins. It has been provisionally named “crocalbumin”. 4. 4. Another major protein in C. porosus albumen has the properties of ovomacroglobulin. 5. 5. Gel-electrophoretic patterns showed that the vitelline membrane in C. porosus lacks the glycoproteins GPI and GPII from the inner layer, although the rest of the pattern is similar to that of the hen.