Thermostable alpha-galactosidase from Thermotoga neapolitana: cloning, sequencing and expression.
Thermostable alpha-galactosidase from Thermotoga neapolitana: cloning, sequencing and expression.
复制标题
来自那不勒斯栖热袍菌的耐热α-半乳糖苷酶：克隆、测序和表达。
作者：
M. R. King;D. Yernool;D. Eveleigh;B. Chassy
从嗜热性极强的热菌（Thermotoga neapolitana）中克隆了一个编码耐热α -半乳糖苷酶的基因并进行了测序。序列分析表明，该蛋白具有552个氨基酸，与大肠杆菌Raf型α -半乳糖苷酶相似，属于糖基水解酶家族第36科。在大肠杆菌中表达的重组α -半乳糖苷酶分子量约为61 kDa，在93℃、pH 7.0条件下具有最佳活性。该酶具有很高的热稳定性，在加热至80℃4小时后仍能保持75%的活性。该酶在大豆糖蜜高温加工中的潜在应用已得到证实。
A gene encoding a thermostable alpha-galactosidase from the hyperthermophile Thermotoga neapolitana was cloned and sequenced. Sequence analysis showed that the 552-amino acid protein is similar to Escherichia coli Raf type alpha-galactosidase and belongs to Family 36 of the glycosyl hydrolases. Recombinant alpha-galactosidase expressed in E. coli has a molecular mass of ca. 61 kDa, and an optimum activity at 93 degrees C at pH 7.0. The enzyme is highly thermostable and retains 75% of activity after heating to 80 degrees C for 4 h. The potential application of the enzyme to high temperature processing of soy molasses has been demonstrated.