Chemical approach for plant protection using chitinase

Plaftchitinases分子量在28000 - 34000 Da之间，是宿主合成的蛋白质，对真菌、病原体或昆虫的攻击具有双重应答作用，可能参与机体的自我防御系统。为了将几丁质酶分子应用于植物保护，从大麦、大豆和山药中分离了几丁质酶，并对纯化的几丁质酶进行了结构和理化性质的分析。结果表明，两个大麦品种的几丁质酶为2类和1类，大豆品种的几丁质酶为3类。对山药几丁质酶的3类和4类反应机理进行了研究。这几种几丁质酶的最适pH、最适温度、pH稳定性和热稳定性都不相同。进一步比较了N-乙酰葡萄糖锇寡聚体的裂解方式，发现3类几丁质酶的底物结合位点有6个亚位点，4类几丁质酶有4个亚位点。

Plaftchitinases with amolecular mass in the range of 28000to34000Da arehost-synthesized proteins that are in duicible in response to fungal, pathogen or insect attack, and may oonrtribute to self-defense systans. To apply the chitinase molecule for a plnt protection, chitinases were separated from barley, soybean ard yam plat.The purified chitinases were analyzed their structure and phy sioochemical prcperties. The results revealed that the chitinase from two barley varieties were class 2 and class 1 and that from soybeen wasass3. The reaction mechanism of class 3 and class 4chitinases were investigated for yam chitinases. Namely, the optimum pH, optimum temperature, pH stabiIity and heat stability of these chitinases were not similar. Further, cleavage pattern for N-acetylgIuc osmine oIigcmer re compared and the result revealed that substrate bindirg site of class 3 chitinase contains 6 subsites and class 4 chitinase contains 4 subsites.