(1,4-alpha-D-galacturonosyl)n+m + H2O = (1,4-alpha-D-galacturonosyl)n + (1,4-alpha-D-galacturonosyl)m. Inhibited by citrus PGIP. On the 2D-gel the determined pI of this protein is: 9.4, its MW is: 44.5 kDa.