Insight into the collagen-degrading activity of a serine protease in the latex of Ficus carica cultivar Masui Dauphine

Ficus carica produces, in addition to the cysteine protease ficin, a serine protease. Earlier study on a serine protease from F. carica cultivar Brown Turkey showed that it specifically degraded collagen. In this study, we characterized the collagenolytic activity of a serine protease in the latex of F. carica cultivar Masui Dauphine. The serine protease degraded denatured, but not undenatured, acid-solubilized type I collagen. It also degraded bovine serum albumin, while the collagenase from Clostridium histolyticum did not. These results indicated that the serine protease in Masui Dauphine is not collagen-specific. The protease was purified to homogeneity by two-dimensional gel electrophoresis, and its partial amino acid sequence was determined by liquid chromatography-tandem mass spectrometry. BLAST searches against the Viridiplantae (green plants) genome database revealed that the serine protease was a subtilisin-like protease. Our results contrast with the results of the earlier study stating that the serine protease from F. carica is collagen-specific.