Participation of the Entner-Doudoroff pathway in Escherichia coli strains with an inactive phosphotransferase system (PTS- Glc+) in gluconate and glucose batch cultures
Participation of the Entner-Doudoroff pathway in Escherichia coli strains with an inactive phosphotransferase system (PTS- Glc+) in gluconate and glucose batch cultures
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DOI：
10.1139/w05-101
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发表时间：
2005-11-01
影响因子：
2.8
通讯作者：
Muñoz, ME
中科院分区：
文献类型：
--
作者：
Ponce, E;García, M;Muñoz, ME
中枢代谢途径的酶活性一直是深入分析的主题;然而，Entner-Doudoroff（艾德）途径最近才开始引起注意。在葡萄糖酸盐和葡萄糖分批培养中研究了大肠杆菌JM 101和PTS- Glc（+）中edd基因敲除的代谢反应，并与先前构建的其他丙酮酸激酶和PTS突变体进行了比较。尽管携带edd基因敲除的菌株与其亲本JM 101和PTS-Glc ' edd与其亲本PTS-Glc（+）之间的比生长速率非常相似，但当在葡萄糖上生长时，获得了比消耗速率和生物量产率的可重复变化.这些结果支持艾德途径不仅参与葡萄糖酸代谢，而且参与大肠杆菌的其他代谢和生化过程。杆菌尽管葡糖酸盐是非PTS碳水化合物，但PTS-Glc '和衍生菌株显示出比生长和葡糖酸盐消耗速率的显著降低。此外，艾德途径对葡萄糖酸盐的总体活性导致PTS-Glc（+）和PTS-Glc（+）pykF突变体的重要增加.用pykA pykF突变体获得的其他结果表明丙酮酸激酶对丙酮酸合成和两种碳源中的能量产生的重要贡献。
The activity of the enzymes of the central metabolic pathways has been the subject of intensive analysis; however, the Entner-Doudoroff (ED) pathway has only recently begun to attract attention. The metabolic response to edd gene knockout in Escherichia coli JM101 and PTS- Glc(+) was investigated in gluconate and glucose batch cultures and compared with other pyruvate kinase and PTS Mutants previously constructed. Even though the specific growth rates between the strain carrying the edd gene knockout and its parent JM101 and PTS- Glc' edd and its parent PTS- Glc(+) were very similar, reproducible changes in the specific consumption rates and biomass yields were obtained when grown on glucose. These results support the participation of the ED pathway not only on gluconate metabolism but on other metabolic and biochemical processes in E. coli. Despite that gluconate is a non-PTS carbohydrate, the PTS- Glc' and derived strains showed important reductions in the specific growth and gluconate consumption rates. Moreover, the overall activity of the ED pathway on gluconate resulted in important increments in PTS- Glc(+) and PTS- Glc(+) pykF mutants. Additional results obtained with the pykA pykF Mutant indicate the important contribution of the pyruvate kinase enzymes to pyruvate synthesis and energy production in both carbon sources.