Glucose Catabolism in Rhizobium japonicum
Glucose Catabolism in Rhizobium japonicum
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日本根瘤菌中的葡萄糖分解代谢
DOI：
10.1128/jb.97.3.1184-1191.1969
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发表时间：
1969
影响因子：
3.2
通讯作者：
G. H. Elkan
中科院分区：
文献类型：
--
作者：
B. B. Keele;P. Hamilton;G. H. Elkan
采用放射性呼吸测定法和主要产能途径中关键酶的测定，对日本根瘤菌ATCC 10324的葡萄糖代谢进行了研究。特异性标记的葡萄糖对静息细胞产生以下结果，值表示为14 CO2释放百分比：C-1= 59%，C-2= 51%，C-3= 45%，C-4= 59%，C-6= 43%。这些值表明葡萄糖仅通过Entner-Doudoroff途径降解。在葡萄糖-酵母提取物-盐培养基中生长的细胞除了C-6碳的阻滞外，基本上给出了相同的模式。发生率为：C-1= 54%，C-2= 42%，C-3= 51%，C-4= 59%，C-6= 32%。已糖激酶、葡萄糖-6-磷酸脱氢酶、转酮醇酶和从6-磷酸葡萄糖酸产生丙酮酸的酶系统被发现存在于这些细胞中。未检测到6-磷酸葡萄糖酸脱氢酶。特异性标记的丙酮酸盐的氧化得到以下14 CO2释放模式：C-1= 78%，C-2= 48%，C-3=37%;乙酸盐的模式为C-1=73%; C-2= 56%。谷氨酸的氧化显示出14 CO2的优先释放速率为C-1 > C-2=C-5 > C-3，4，而从琥珀酸酯的C-1和C-4碳比从C-2和C-3碳获得更高的14 CO2产率。这些数据与葡萄糖氧化的分解代谢途径Entner-Doudoroff途径和三羧酸循环的运作是一致的。日本的
Glucose catabolism in Rhizobium japonicum ATCC 10324 was investigated by the radiorespirometric method and by assaying for key enzymes of the major energy-yielding pathways. Specifically labeled glucose gave the following results for resting cells, with values expressed as per cent 14CO2 evolution: C-1=59%, C-2=51%, C-3=45%, C-4=59%, and C-6=43%. These values indicate that glucose was degraded by the Entner-Doudoroff pathway alone. Cells which grew in glucose-yeast extract-salts medium gave essentially the same pattern except for retardation of the C-6 carbon. The rates were: C-1=54%, C-2=42%, C-3=51%, C-4=59%, and C-6=32%. Hexokinase, glucose-6-phosphate dehydrogenase, transketolase, and an enzyme system which produces pyruvate from 6-phosphogluconate were found to be present in these cells. No 6-phosphogluconate dehydrogenase was detected. Oxidation of specifically labeled pyruvate gave the following 14CO2 evolution pattern: C-1=78%, C-2=48%, and C-3=37%; the pattern from acetate was C-1=73%; and C-2=56%. Oxidation of glutamate showed the preferential rate of 14CO2 evolution to be C-1 > C-2=C-5 > C-3, 4, whereas a higher yield of 14CO2 was obtained from the C-1 and C-4 carbons of succinate than from the C-2 and C-3 carbons. These data are consistent with the operation of the Entner-Doudoroff pathway and tricarboxylic acid cycle as the catabolic pathways of glucose oxidation in R. japonicum.