中文摘要：

在这研究，我们证实了那至少三 endo -- 1,4-glucanases 在巨大的蜗牛的消化果汁存在， Achatina fulica ferussac，由刚果红染色试金。这些酶之一，新奇 endo -- 1,4-glucanase (AfEG22 ) ，是由胶化过滤，阴离子交换，和恐水病的相互作用层析的净化的 29.5 褶层。净化的酶的 carboxymethyl 纤维素(CMC ) hydrolytic 活动是 12.3 U/mg 蛋白质。AfEG22 的分子的团是 MALDI-TOF 决定的 22081 Da。N 终端氨基酸定序揭示了 EQRCTNQGGILKYYNT 的一个序列，它没在强风数据库与任何蛋白质有重要相同。为向 CMC 的 hydrolytic 活动的最佳的 pH 和温度是 pH 4.0 和 50

英文摘要：

In this study, we confirmed that at least three endo-β-1,4- glucanases existed in the digestive juice of the giant snail, Achatinafulicaferussac, by Congo red staining assay. One of these enzymes, a novel endo-β-1,4-glucanase （AfEG22）, was purified 29.5-fold by gel filtration, anion exchange, and hydrophobic interaction chromatotogphy. The carboxymethyl cellulose （CMC） hydrolytic activity of the purified enzyme was 12.3 U/mg protein. The molecular mass of AfEG22 was 22081 Da determined by MALDI- TOF. N-terminal amino acid sequencing revealed a sequence of EQRCTNQGGILKYYNT, which did not have significant homology with any proteins in BLAST database. The optimal pH and temperature for hydrolytic activity toward CMC were pH 4.0 and 50℃, respectively. AfEG22 was stable between pH 3.0 and pH 12.0 when incubated at 4℃ for 3 h or at 37℃ for 1 h. The enzyme remained more than 80% activity between pH 4.5 and pH 7.0 after incubation at 50℃ for 1 h. AfEG22 possessed excellent thermostability as more than 70% activity was remained after incubation at 60℃ for 3 h. Substrate specific analysis revealed that AfEG22 was a typical endo- β-1,4-glucanase. This is the first time to report a novel endo-β-1,4-glucanase with high stability from the digestive juice of A. fulica.