The hybrid enzymes from α-aspartyl dipeptidase and l-aspartase

With combinative functionalities as well as the improved activity and stability, the novel hybrid enzymes (HEs) from the heterogeneous enzymes of α-aspartyl dipeptidase (PepE, monomer) and l-aspartase (l-AspA, tetramer) were constructed successfully by gene random deletion strategy. The wild-type hybrid enzyme (WHE) and the evolved hybrid enzyme (EHE) were selected, respectively, upon the phenotype and the enzyme activity. The relative activity of the WHE tested was about 110% of the wild-type PepE and 26% of the wild-type l-AspA, whilst the activity of EHE was about 340% of the PepE and 87% of the l-AspA. In comparison to its individual wild-type enzymes, the EHE exhibited an improved thermostability, when examined at the enzyme concentration of 10−7 mol/L, but the WHE showed a reduced thermostability. The activity of the EHE was about 3-fold compared to that of the WHE. The current results give a good example that the hybridization of enzymes could be attained between the monomer and multimer enzymes. In addition, they also indicate that construction hybrid enzyme from evolved enzymes is feasible.