EFFECT OF OXYGEN CONCENTRATION AND GROWTH-RATE ON GLUCOSE-METABOLISM POLY-BETA-HYDROXYBUTYRATE BIOSYNTHESIS AND RESPIRATION OF AZOTOBACTER-BEIJERINCKII
EFFECT OF OXYGEN CONCENTRATION AND GROWTH-RATE ON GLUCOSE-METABOLISM POLY-BETA-HYDROXYBUTYRATE BIOSYNTHESIS AND RESPIRATION OF AZOTOBACTER-BEIJERINCKII
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DOI：
10.1099/00221287-110-2-393
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发表时间：
1979-01-01
期刊：
影响因子：
--
通讯作者：
DAWES, EA
中科院分区：
文献类型：
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作者：
CARTER, IS;DAWES, EA
在连续培养条件下，研究了溶氧浓度对固氮假单胞菌葡萄糖代谢、聚-β-羟基丁酸酯(PHB)合成和呼吸的影响。Entner-Doudoroff酶活性随着供氧量的增加而降低，而葡萄糖-6-磷酸脱氢酶活性不受影响；β-酮硫醇酶和乙酰乙酰-CoA还原酶的活性下降更明显，反映了PHB含量的下降。O2和CO2的代谢商随着供氧量的增加而迅速增加，与固氮酶的呼吸保护作用相一致。除β-酮硫醇酶和乙酰乙酰-辅酶A还原酶活性在氧气限制下均以最高稀释速率(0.23h-1)下降外，在O2和N限制下，所有酶和果糖-1，6-二磷酸缩醛酶的比活力均随稀释速率的增加而增加。Entner-Doudoroff序列作为贝耶林克曲霉葡萄糖代谢的主要途径不受氧气浓度和生长速率的影响。
The effect of dissolved O2 concentration on glucose metabolism, poly-.beta.-hydroxybutyrate (PHB) synthesis and respiration of N2-fixing A. beijerinckii was investigated over a range of values spanning O2 limitation and sufficiency (N limitation) in continuous culture. The activities of the Entner-Doudoroff enzymes decreased with increasing O2 supply while glucose-6-phosphate dehydrogenase was unaffected; .beta.-ketothiolase and acetoacetyl-CoA reductase decreased more markedly, reflecting the fall in PHB content. The metabolic quotients for O2 and CO2 increased rapidly with increasing O2 supply, in keeping with the respiratory protection of nitrogenase. The specific activities of all these enzymes, and also of fructose-1,6-bisphosphate aldolase, increased with increasing dilution rate under either O2 or N limitation, except that both .beta.-ketothiolase and acetoacetyl-CoA reductase activities fell at the highest dilution rate (0.23 h-1) under O2 limitation. The role of the Entner-Doudoroff sequence as the major route of glucose metabolism in A. beijerinckii was unaffected by O2 concentration and growth rate.