Expression of Apalbumin1 of Apis cerana cerana in the Larvae of Silkworm, Bombyx mori

Royal jelly (RJ) is a thick, milky material produced by both the hypopharyngeal and the mandibular glands of nurse honeybees. The main proteins of RJ, named apalbumins or major royal jelly proteins (MRJPs), have multiple biological functions. Apalbumin1 is the most abundant glycoprotein of RJ. In this study, Bacmid-apalbumin1 was constructed for Apis cerana cerana using the newly established Bac-to-Bac/BmNPV baculovirus expression system (BES). This procedure allowed us to obtain the recombinant A. cerana cerana (Acc) apalbumin1 (rAccapalbumin1) from the hemolymph of silkworm larvae through the BmNPV bacmid system, 96 h postinfection. The rAccapalbumin1 was then purified by Ni-NTA spin columns and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting. A 55 kDa protein with good solubility was then obtained. The peptide Ile-Phe was identified from trypsin production of rAccapalbumin1. Such a peptide has been reported to have an anti hypertensive ability. Our results have therefore potential applications in biomedical research and open new perspectives for the study of apalbumins.