A novel and highly efficient purification procedure for native human dipeptidyl peptidase 3 from human blood cell lysate.

Dipeptidyl amino-peptidase 3 (DPP3) is an aminopeptidase involved in peptide degradation, including hormone peptides as angiotensin II and enkephalins. DPP3 plasma activity increases in septic patients and correlates with mortality risk. However, the exact physiological role of DPP3 remains unclear and animal studies are necessary to reveal the function of DPP3 in vivo. To this demand, we developed a two-step purification procedure for isolation of native human DPP3 from blood cell lysate (BCL) that is suitable for in vivo applications. With the use of monoclonal antibodies coupled to beads in combination with an ion-exchange chromatography, we recovered 68% of human DPP3 activity from BCL with a purity of ≥ 95%. Purified human DPP3 was assayed for activity and protein concentration using recently published DPP3-activity- and immunoassays. Additionally, protein stability and storage in relevant buffers were tested. Our results provide a promising strategy for fast and efficient isolation of human DPP3. The purified human DPP3 represents the native state of DPP3, suitable for future in vivo applications to investigate the physiological role of DPP3 and its involvement in pathophysiological conditions.