Cloning of the malic enzyme gene from Corynebacterium glutamicum and role of the enzyme in lactate metabolism
Cloning of the malic enzyme gene from Corynebacterium glutamicum and role of the enzyme in lactate metabolism
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DOI：
10.1128/aem.66.7.2981-2987.2000
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发表时间：
2000-07-01
影响因子：
4.4
通讯作者：
Guyonvarch, A
中科院分区：
文献类型：
--
作者：
Gourdon, P;Baucher, MF;Guyonvarch, A
苹果酸酶是已知存在于谷氨酸棒状杆菌中的至少五种酶之一，能够进行羧基化和脱羧化反应，偶联糖酵解和三羧酸循环。到目前为止，还没有关于苹果酸酶在这种细菌中的生理作用的信息。已克隆并测定了谷氨酰胺（C. glutamicum）雄性基因。该基因编码的蛋白已被纯化到均匀性，并建立了生化特性。生化特征表明脱羧作用与NADPH的产生有关。男性基因被破坏或过表达的谷氨酰胺菌株在乙酸和葡萄糖的生长过程中没有可检测到的表型，但在乳酸代谢过程中表现出显著的生长行为改变。野生型表现出短暂的乳酸指数生长期，然后是线性生长期的特征。这种生长模式在malE中断菌株（Delta malE）中进一步加强。然而，过表达malE的菌株保持指数增长，直到所有乳酸消耗殆尽。该菌株在培养基中积累的丙酮酸明显多于其他菌株。
Malic enzyme is one of at least five enzymes, known to be present in Corynebacterium glutamicum, capable of carboxylation and decarboxylation reactions coupling glycolysis and the tricarboxylic acid cycle. To date, no information is available concerning the physiological role of the malic enzyme in this bacterium. The malE gene from C. glutamicum has been cloned and sequenced. The protein encoded by this gene has been purified to homogeneity, and the biochemical properties have been established. Biochemical characteristics indicate a decarboxylation role linked to NADPH generation. Strains of C. glutamicum in which the malE gene had been disrupted or overexpressed showed no detectable phenotype during growth on either acetate or glucose, but showed a significant modification of growth behavior during lactate metabolism. The wild type showed a characteristic brief period of exponential growth on lactate followed by a linear growth period. This growth pattern was further accentuated in a malE-disrupted strain (Delta malE). However, the strain overexpressing malE maintained exponential growth until all lactate had been consumed. This strain accumulated significantly larger amounts of pyruvate in the medium than the other strains.