Inactive dipeptidyl peptidase 1, also known as Dipeptidyl peptidase IV-related protein 3, Dipeptidyl peptidase X, Dipeptidyl peptidase-like protein 2, DPRP-3, DPL2 and DPP1, is a single-pass type II membrane protein which belongs to thepeptidase S9B family.DPPIV subfamily. It may modulate cell surface expression and activity of the potassium channels KCND1 and KCND2. DPP1 / DPRP3 has no detectable protease activity, most likely due to the absence of the conserved serine residue normally present in the catalytic domain of serine proteases. However, it does bind specific voltage-gated potassium channels and alters their expression and biophysical properties. Genetic variations in DPP1 are associated with susceptibility to asthma (ASTHMA). The most common chronic disease affecting children and young adults. It is a complex genetic disorder with a heterogeneous phenotype, largely attributed to the interactions among many genes and between these genes and the environment. It is characterized by recurrent attacks of paroxysmal dyspnea, with weezing due to spasmodic contraction of the bronchi.