Examination of proteins contained in allergen scratch extract Torii^® egg white, egg yolk, and cow's milk

Abstract

Background:

In Japan, allergen scratch extract Torii^® (SE) is used as a standard reagent for skin prick tests; however, there is no clarity on the protein content of the extract is not clear.

Methods:

Sodium dodecyl sulfate-polyacrylamide electrophoresis (SDS-PAGE) and immunoblotting were conducted to analyze SE derived from egg white, egg yolk, and cow's milk, and compared to those of raw egg white, raw egg yolk, and cow's milk, respectively.

Results:

The protein content of each SE was found to be lower than that of the respective food sources. SDS-PAGE revealed a band in the egg white SE similar to that in raw egg white, and immunoblotting confirmed the presence of sufficient amounts of ovalbumin and ovomucoid. Egg yolk SE demonstrated trace amounts of ovalbumin and ovomucoid. Conversely, cow's milk SE contained little amount of casein but significant amounts of α-lactalbumin and β-lactoglobulin.

Conclusion:

Egg yolk SE contained trace amounts of egg white components, while cow's milk SE mainly consisted of whey components.