배추흰나비 (Pieris rapae L.)는 2가지의 주요 난황단백질을 가지고 있으며, 그중 하나가 난소와 암컷 혈림프에 존재하며 수컷에서는 존재하지 않는 vitellin이며 다른 하나는 암, 수 혈림프에 공히 존재함이 밝혀졌다. 이러한 후자의 단백질을 난황단백질(YP)이라 칭하였으며 이 단백질의 전구체가 암수 혈림프와 지방체에 함께 존재한다는 것이 이차원 전기영동법과 면역적 방법에 의해 확인되었다.
Ovarian extract of cabbage butterfly, Pieris rapae L. has two major yolk proteins. One of them was identified as vitellin since it was present in female hemolymph but not in male hemolymph and the other protein was present in hemolymph of both female and male. This ovarian protein was designated yolk protein (YP). The yolk protein precursor in female hemolymph and fat body was similar to that of the male as the two proteins migrated identically on two-dimensional electrophoresis and gave the same reaction in immunoblotting experiments.
