Dipeptidyl-peptidase 3 is an enzyme that in humans is encoded by the DPP3 gene. This gene encodes a protein that is a member of the S9B family in clan SC of the serine proteases. This cytoplasmic protein binds a single zinc ion with its zinc-binding motif (HELLGH) and has post-proline dipeptidyl aminopeptidase activity, cleaving Xaa-Pro dipeptides from the N-termini of proteins. Increased activity of this protein is associated with endometrial and ovarian cancers. Alternate transcriptional splice variants have been characterized. Dipeptidyl-peptidase 3 has been found to act as a myocardial depressant factor. Procizumab, a specific antibody for dipeptidyl-peptidase 3, was found to improve cardiac and renal function in a mouse model of heart failure. In human studies, higher levels of circulating DPP3 protein in cardiogenic shock patients indicated a more severe disease course, with a higher risk of refractory cardiogenic shock and death.