Degradation caused by pH-mediated destabilization is highly
dependent on the stability of the recombinant protein itself, which
is usually increased by glycosylation and disulfide bond formation
[21]. Because Lipase GH1 is a glycosylated protein, we hypothesized
that glycosylation helps promote the enzyme stability. Serine and
aspartic proteases (both secreted by P. pastoris) are activated at
low pH values, and this fact may account for the pH dependence of
proteolytic activity [21].