Characterization of a Serine Carboxypeptidase Hoscp from Holotrichia Oblita Faldermann (Coleoptera: Scarabaeoidea)

摘要

In this report, we have identified a novel serine carboxypeptidase, named HoSCP, from the midgut of a destructive agricultural and landscape pest, Holotrichia oblita. HoSCP cDNA gene was cloned by immunoscreening method. Sequence analysis showed about 49kDa HoSCP consists of 457 amino acid residues with a 17-amino acid signal peptide and a conserved peptidase S10 family domain. The HoSCP protein was expressed as a recombinant protein in the yeast Pichia pastoris and enzyme activity assay showed that recombinant HoSCP had serine carboxypeptidases activity. Results of carboxypeptidase activities indicated that optimal enzyme activity occurs at pH 8.0, Compared with late 2nd-instar and late 3rd-instar larvae, midgut tissues of early 2nd-instar and early 3rd-instar larvae had higher levels of serine carboxypeptidase activity. The study would provide a foundation for the further research of the structure and function of HoSCP of H. oblita.