Human
meprin β (h-
meprin β), a single-
zinc metalloendoprotease of the
astacin family, is potentially involved in disorders such as
fibrosis and
Alzheimer's disease. Here, we describe the expression of the
enzyme in the yeast Pichia pastoris. The N-terminal
signal sequence was replaced by the α-leader of Saccharomyces, enabling efficient secretion of the mature
enzyme, harboring either an N-terminal or C-terminal His-tag. The purification by affinity and hydrophobic interaction chromatography resulted in isolation of 58.4 mg/l of homogenous human pro-
meprin β from fermentation broth. The activated
enzyme isolated from yeast (yh-
meprin β) displayed virtually identical enzymatic activity as h-
meprin from a mammalian cell line. Furthermore, the yh-
meprin β was N-glycosylated and secreted as a dimer with a molecular mass of 148 kDa.
Endoglycosidase H treatment generated a
protein with a molecular mass of 133 kDa, but essentially unchanged kinetic parameters. Thus, our data suggest that human
meprin β expressed in P. pastoris displays virtually identical parameters as
meprin from other sources. The high yield of
protein expression, the ease of purification and the deglycosylation in its native state appear to favor further studies aiming at inhibitor screening and structure-based inhibitor refinement.