Abstract
Active β1,3-N-acetylglucosaminyltransferase 2 (β3GnT2) was produced in the baculovirus expression system (BES) and in stably transformed insect Tn-5B1-4 cells. β3GnT2 was expressed as a secreted fusion protein with GFPuv with prepromelittin signal sequence from honeybee. The β3GnT activities of the culture supernatant in BES (Tn-5B1-4 cells) without or with the addition of the protease inhibitor, leupeptin, were 0.68 and 2.01 mU/ml, respectively. The stably transformed Tn-5B1-4 cells (Tn-pXme11) exhibited a β3GnT activity of 6.83 mU/ml, which was 3.4-fold higher than that observed for BES with the leupeptin addition. The purity of fusion protein purified from the culture supernatant of the Tn-pXme11 was higher than 95% in contrast with that purified from the culture supernatant of the baculovirus-infected cells which contained low-molecular-weight fragments of the fusion protein. The stably transformed cell line is more suitable than BES for the efficient production of the secretory protein, β3GnT2.
