Production of recombinant human bile salt stimulated lipase and its variant in Pichia pastoris

hBSSL and its truncated variant hBSSL-C cDNA clones were expressed in Pichi a pastoris using two different signal peptides, native signal peptide and i nvertase signal peptide, respectively, to facilitate secretion of the recom binant proteins into the culture medium. Both recombinant proteins were sec reted into the culture medium to a level of 45-50 mg/liter in shake flask c ultures. Native signal peptide of hBSSL was recognized in P, pastoris and w as cleaved at the same site as in humans. The level of expression of the hB SSL gene was found to be dependent on the number of its copies integrated i nto the host chromosome. The multicopy transformant clone was found to be v ery stable. When grown and induced in a fermentor, the level of accumulatio n of the recombinant hBSSL in the culture medium improved from 50 mg/liter in shake flask cultures to 300 mg/liter. The recombinant hBSSL purified fro m the culture supernatant was found to be similar to the native hBSSL in it s biochemical properties except for the lectin-binding profile. (C) 1998 Ac ademic Press.