Distribution of chitinases and characterization of two chitinolytic enzymes from one-year-old Korean Ginseng (Panax ginseng C.A. Meyer) roots

We report the tissue-specific distribution of chitinolytic activity in Korean ginseng root and characterize two 31-kDa chitinolytic enzymes. These two enzymes (SBF1 and SBF2) were purified 70- and 81-fold with yields of 0.75 and 1.25%, respectively, and exhibited optimal pH and temperature ranges of 5.0-5.5 and 40-50(o)C. With [(3)H]-chitin as a substrate, K(m) and V(max) values of SBF1 were 4.6 mM and 220 mmol/mg-protein/h, respectively, while those of SBF2 were 7.14 mM and 287 mmol/mg-protein/h. The purified enzymes showed markedly less activity with p-nitrophenyl-N-acetylglucosaminide and fluorescent 4-methylumbelliferyl glycosides of D-N-acetylglucosamine oligomers than with [(3)H]-chitin. End-product inhibition of both enzymes demonstrated that both are endochitinases with different N-acetylglucosaminidase activity. Furthermore, the NH(2)-terminal sequence of SBF1 showed a high degree of homology with other plant chitinases whereas the NH(2)-terminal amino acid of SBF2 was blocked. [BMB reports 2010; 43(11):726-731].