Proteins of the vitelline membrane of quail (Coturnix coturnix japonica) eggs. Poult Sci 72

ABSTRACT Proteins in the vitelline membrane of quail (Coturnix coturnix japonica) eggs were analyzed by SDS-PAGE. Ten major bands, molecular mass ranging from 14.5 to 285 kDa, can be clearly distinguished. Two bands corresponding to the molecular masses of 33 and 175 kDa were detected in the inner layer of the membrane and both were stained with periodic acid-Schiff reagent, indicating that they are glycoproteins. Nine bands were detected in the outer layer of the membrane. Among them, 265- and 285-kDa bands were glycoproteins. During storage of eggs at 25 C, the yolk index significantly decreased. Among the 10 proteins of the vitelline membrane, a decrease in the 20-kDa protein was most prominent, disappearing after 5 days of storage. The 16.5- and 175-kDa protein bands were also less prominent, whereas the 40- and 61-kDa proteins increased during storage. These changes in the proteins of the vitelline membrane were also observed in eggs stored at 4 C, although the changes occurred more slowly than that noted from the eggs stored at 25 C. (Key words: quail eggs, vitelline membrane, yolk index, storage, glycoprotein