Comparative Studies on Physical and Chemical Property of Avian Eggs

5. Horizontal Polyacrylamide Gradient Gel Electrophoretograms of Chicken (Gallus domesticus) Egg White Proteins

Abstract

Horizontal polyacrylamide gradient gel electrophoretograms of chicken (White Leghorn) egg white were studied. The egg white protein bands were separated into 15 electrophoretic zones (Nos. 1-15). A new protein polymorphism were observed in No. 9 (G₄) which migrated between ovoglobulin G₃ and G₂ bands. Three variants in zone Nos. 7 and 8 are controlled by the G₃ locus with 2 autosomal codominant alleles: G₃^A and G₃^B. The gene frequency of G₃^A and G₃^B was 0.100 and 0.900, respectively. Three variants in zone No. 9 are controlled by G₄ locus with 2 autosomal codominant alleles: G₄^A and G₄^B. The gene frequency of G₄^A and G₄^B was 0.891 and 0.109, respectively.
Zone Nos. 3, 4 and 5 are ovalbumin bands. Three variants in ovalbumin bands are controlled by Ov locus with 2 autosomal codominant alleles: Ov^A and Ov^B as previously reported7). The gene frequency of Ov^A and Ov^B was 0.900 and 0.100, respectively. Ov^A and Ov^B were closely linked with G₃^B and G₃^A, respectively.
Zone No. 10 is ovoglobulin G₂ bands. Three variants in zone No. 10 are controlled by G₂ locus with 2 autosomal codominant alleles, G₂^A and G₂^B, as previously reported2). The gene frequency of G₂^A and G^B was 0.305 and 0.695, respectively. Zone No. 13 was transferrin bands. All of the phenotypes of transferrin were B/B homozygotes.
Heating fresh egg white (pH 8.9) for 5min at 70°C altered electrophoretic patterns. Prealbumins (No. 1 and 2), ovalbumin (Nos 3, 4 and 5), ovoglobulin G₃ (Nos. 7 and 8), ovoglobulin G₄ (No. 9), one of the pretransferrins (No. 11) and transferrin (No. 13) became less intense. After being heated for 5min at 70°C, ovoglobulin G₃ and G₄, ovotransferrin and pretransferrin (No. 12) were nearly absent from electrophoretic patterns.
In electrophoretograms of egg white stored for 3 or 5 weeks at 25°C (pH 9.6), intensity of prealbumins (No. 1 and 2), ovalbumin, and ovoglobulin G₃ did not decrease after being heated for 5min at 70°C. Ovoglobulin G₂ (No. 10), ovomucoid (No. 6), the other pretransferrin (No. 12) and posttransferrins (No. 14 and 15) were stable after being heated at 70°C for 5min either in 0, 3 and 5 weeks of storage. On the other hand, ovoglobulin G₄, ovotransferrin and pretransferrin (No. 11) were not stable after being heated at 70°C for 5min either in 0, 3 or 5 weeks of storage.