Purification and characterization of a cold-adapted isocitrate lyase and expression analysis of the cold-inducible isocitrate lyase gene from the psychrophilic bacterium Colwellia psychrerythraea
Purification and characterization of a cold-adapted isocitrate lyase and expression analysis of the cold-inducible isocitrate lyase gene from the psychrophilic bacterium Colwellia psychrerythraea
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冷适应异柠檬酸裂解酶的纯化和表征以及嗜冷细菌冷红菌冷诱导异柠檬酸裂解酶基因的表达分析
DOI：
10.1007/s00792-002-0271-x
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发表时间：
2002
期刊：
影响因子：
2.9
通讯作者：
Y. Takada
中科院分区：
文献类型：
--
作者：
Seiya Watanabe;N. Yamaoka;N. Fukunaga;Y. Takada
从嗜冷菌Colwellia psycherythraea中分离纯化了异柠檬酸裂解酶（ICL），并对其性质进行了研究。亚基分子量为64 kDa，比其它细菌ICL的亚基分子量大。其最适反应温度为25°C，对底物（DL-异柠檬酸）的Km值在15°C时最小，催化效率（kcat/Km）在20°C时最大。此外，该酶是显著不耐热的，并且通过在30°C下孵育2分钟而完全失活。这些特征表明该菌的ICL是一种典型的冷适应酶。对C. psychrythraaICL与近缘嗜冷菌Colwelliamaris的ICL相似。表达C.发现低温和培养基中的乙酸盐可诱导psychrythraaICL。ICL的催化性质的冷适应和其基因在低温下的刺激表达强烈表明，这种酶对于该细菌在寒冷环境中的生长是重要的。
Isocitrate lyase (ICL) fromColwellia psychrerythraea, a psychrophilic bacterium, was purified and characterized. The subunit molecular mass was 64 kDa, which is larger than that of other bacterial ICLs. The optimal temperature for its activity was 25°C, the value ofKmfor the substrate (DL-isocitrate) was minimum at 15°C, and the catalytic efficiency (kcat/Km) value was maximum at 20°C. Furthermore, the enzyme was remarkably thermolabile and completely inactivated by incubation for 2 min at 30°C. These features indicate that ICL from this bacterium is a typical cold-adapted enzyme. A partial amino acid sequence of theC. psychrerythraeaICL was very similar to that of the closely related psychrophileColwellia maris. Expression of the gene encoding theC. psychrerythraeaICL was found to be induced by low temperatures and by acetate in the medium. The cold adaptation of the catalytic properties of ICL and the stimulated expression of its gene at low temperatures strongly suggest that this enzyme is important for the growth of this bacterium in a cold environment.