Recombinant pro-Der p 1 expressed in yeast Pichia pastoris was convertible into the prosequence-removed mature Der p 1 with full activities of cysteine protease and IgE-binding with or without N-glycosylation of the mature sequence as well as pro-Der f 1. The active recombinant variants will be the basis for various future studies. The major N-terminus of pro-Der p 1 with low proteolytic activity was the putative signal-cleavage site, while that of pro-Der f 1 contained not only the equivalent site but also 21 residues downstream, and pro-Der f 1 retained significant activity. Contribution of the N-terminal region of the Der p 1 prosequence including an N-glycosylation motif on effective inhibition of proteolytic activity of pro-Der p 1 was suggested.