Expression and Purification of Soluble, Biologically Active Recombinant Dipeptidyl Peptidase 4 (DPP4/CD26/ADAbp) Comprising the Extracellular Domain in the Yeast, Pichia pastoris

Purpose: To investigate Pichia pastoris expression system for producing clinically usable, high-quality dipeptidyl peptidase 4 recombinant protein. Methods: The yeast, Pichia pastoris, expression system was used for the production of the human recombinant dipeptidyl peptidase 4 as a secreted form. The full-length human dipeptidyl peptidase 4 corresponding to the amino acid 31-766 was subcloned into a Pichia pastoris expression vector, pPICZ , and transformed to Pichia pastoris X33 cells. Results: The human recombinant dipeptidyl peptidase 4 protein was expressed enzymatically as active human rDPP4(31-766) as secreted form in the yeast P. pastoris, purified and monitored its biological activity. The test DPP4 recombinant protein induced a significant increase of DDP4 activity at 10, 20 and 30 min incubation time (p < 0.05) and at 40 min (p < 0.001). A similar pattern was found for the commercial (standard) DPP4 protein at 10, 20 and 30 min (p < 0.05) and at 40 min (p < 0.001). The high standard deviation (SD) associated with the mean value for the DPP4 activity is due to incubation time sometimes associated with high DPP4 values. The values were much higher than in other groups as expected. Conclusion: Human recombinant dipeptidyl peptidase 4(31-766) protein in the yeast Pichia pastoris, obtained using the technique employed in this study can further improve production efficiency and costs of human recombinant dipeptidyl peptidase 4 and other recombinant proteins.