Heterologous Expression of the Astacin Protease Meprin β in Pichia pastoris

Meprins are zinc-dependent proteases of the metzincin superfamily of metalloproteases. The enzymes are extracellular multi-domain proteins which are stabilized by disulfide bridges, dimerization, and glycosylation. Due to their complex structure, recombinant expression was first established in mammalian and insect cells. However, these methods have several disadvantages such as high costs and the low yields. For this reason, yeast is often considered a preferable expression system. Here, we describe the manipulation and secretory expression of human meprin β in the methylotrophic yeast P. pastoris. We show that the position of the affinity tag strongly influences the yield of expression, favoring fusion of the affinity tag at the C-terminus.