Glycosylation – found in 50 % of all mammalian proteins – is a particularly important feature in human Kallikreins. The Kallikrein-related Peptidase 2 (KLK2), which plays an important role in prostate cancer, has now been successfully expressed in glycosylated, homogenous and active form with LEXSY (the L. tarentolae based expression system). This allowed for the first time to study the effect of glycosylation on the activity of this key protein, showing that LEXSY is the expression system of choice for glycosylated proteins.
Figure 1 – Left: Purified KLK2 and detection of glycosylation by removal with PNGase F. The glycosylated protein is very homogenous and does not show double bands.
Right: Model of human KLK2. The glycan residue (blue and green) is a significant part of the protein and has a substantial effect on its activity. From Guo et al., 2016.