HIGH-LEVEL EXPRESSION OF A FROG ALPHA-AMIDATING ENZYME, AE-II, IN CULTURED-CELLS AND SILKWORM LARVAE USING A BOMBYX-MORI NUCLEAR POLYHEDROSIS-VIRUS EXPRESSION VECTOR

A Xenopus laevis peptidyl C-terminal alpha-amidating enzyme (AE-II) gene, modified by deletion of a region encoding the putative membrane-spanning domain and the putative C-terminal cytosolic tail, was expressed in BoMo-15AIIc insect cells and silkworm larvae using a Bombyx mori baculovirus expression vector system. The expressed enzyme was identified predominantly in the culture medium and the hemolymph of silkworm larvae, indicating successful secretion of the expressed AE-II. The level of recombinant enzyme in the larval hemolymph at 4 days post-infection (40 mug/ml) was more than 100-fold the peak levels found in the culture medium (250 ng/ml). The enzyme activity in the larval hemolymph at 4 days post-infection was 3700 units/ml.