Enhanced expression of recombinant elastase in Pichia pastoris through addition of N-glycosylation sites to the propeptide.

N-Glycosylation is a common form of protein post-translational modification in Pichia pastoris and greatly affects folding and secretion. The propeptide of the Pseudomonas aeruginosa elastase (PAE) is indispensable for proper folding and secretion of the enzyme. We have studied the effect of introducing N-glycosylation sites to the propeptide of the recombinant elastase (rPAE) on its expression levels in P. pastoris. Addition of N-glycosylation sites to the propeptide at N51 or N93 enhanced rPAE production levels by 104 or 57%, respectively, while addition at N11 or N127 led to a 25 or 50% decrease, respectively. The introduced N-glycosylation sites in the propeptide at these four sites exerted a null effect on the N-glycosylation degree of mature rPAE.