Characterization of an antimicrobial Chitinase Purified from the Grapefruit Extract

자몽 추출물로부터 분리된 항균성 Chitinase의 특성

An antimicrobial chitinase was purified from grapefruit extract and its properties were characterized. The chitinase was purified with a single step chromatography on regenerated chitin affinity gel column. The molecular weight of the purified chitinase was 29 kDa. The grapefruit extract contained the chitinase protein more than 50% of its total soluble proteins measured by coomassie stained protein bands. When the purified chitinase was incubated with polymers of N-acetylglucosamine (NAG), such as mycelia of Fusarium oxysproum and swollen chitin, they were degraded to oligosaccharides, and the oligosaccharides were then further hydrolyzed by the same enzyme to monomer and dimer of NAG. This result suggests that the chitinase contained both endo- and exo- chitinase activities. The chitinase was stable to heat and pH treatment; its activity was not diminished by the heat treatment upto 7$0^{\circ}C$ for 1 hr, and it showed a pH stability in the range of pH 4.0 to 12.0.