Production and purification of human fibroblast collagenase (MMP-1) expressed in the methylotrophic yeast Pichia pastoris

The cDNA that encodes the proenzyme form of human fibroblast collagenase (proMMP-1) was expressed in the methylotrophic yeast Pichia pastoris. The proMMP-1 encoding DNA was fused to the Saccharomyces cerevisiae pre-pro alpha-mating factor secretion signal in the P. pastoris pPIC9 expression plasmid, transformed into strain GS115 (His-), and His+ Muts (slow methanol utilization) transformants were selected. Full-length proenzyme and processed forms of the protein could be detected in yeast culture supernatants following shake flask and 10-liter fermentations. The protein was purified to greater than 95% homogeneity. The recombinant proMMP-1 was comparable to the native fibroblast material based on (i) migration of the full-length molecule as a 52-kDa protein on reducing SDS-PAGE, (ii) correct N-terminal amino acid sequence, (iii) activation of the full-length molecule by 4-amino-phenylmercuric acetate to yield processed protein species, (iv) degradation of gelatin as monitored by zymogram gels, and (v) enzymatic activity. These data suggest that the P. pastoris expression system offers a convenient and efficient means to produce and purify MMP-1.