Rehmannia chitinases were extracted from the leaves of Rehmannia glutinosa under acidic conditions (pH 2.9). We purified a 28.6-kDa chitinase, designated as P2, from crude extract to homogeneity by (NH4)2SO4 precipitation, chromatography with regenerated chitin affinity and hydrophobic interaction column, and preparative native PAGE. Isolated P2 showed maximum chitinase activity at pH 5.0 and 60°C, and had a isoelectric point of 8.46. P2 produced only (GlcNAc)2 from (GlcNAc)4-6 and regenerated chitin. Based on these results, we arrived at the conclusion that P2 was a basic exochitinase.
Keywords: Rehmannia glutinosa; basic chitinase; defense-related protein; exochitinase.