Carter B L, Bull A T, Rowley B I, Pirt S J
J Bacteriol. 1971 Oct;108(1):309-13. doi: 10.1128/jb.108.1.309-313.1971.
The maintenance coefficient of glucose-limited Aspergillus nidulans chemostat cultures at 30 C was 0.018 g per g (dry weight) per hr for glucose and 0.55 mmoles per g (dry weight) per hr for oxygen. These values can only be approximate because melanin was produced by the mold at low growth rates and because it is unlikely that this polymer contributed to the maintenance energy requirement although it contributed to the dry weight. Biomass (defined here as dry weight minus melanin) was used to calculate a more meaningful maintenance coefficient for glucose (0.029 g of glucose per g of biomass per hr). At the highest growth rates examined, a nonlinear relationship between growth rate and glucose utilization rate was obtained, suggesting a qualitative change in the metabolic activities of the mold at high growth rates. The oxidative capacity of the mold was highest at the highest growth rates. This observation indicates that the increased substrate utilization rate observed at the higher growth rates is a reflection of enhanced enzyme synthesis. This hypothesis was verified by assaying the specific activities of several enzymes at different growth rates. However, in contrast to all the other enzymes assayed, the activities of reduced nicotinamide adenine dinucleotide phosphate: (acceptor) oxido-reductases were highest at the lowest growth rates.
在30℃下，葡萄糖限制的构巢曲霉恒化器培养物的维持系数，对于葡萄糖而言为每克（干重）每小时0.018克，对于氧气而言为每克（干重）每小时0.55毫摩尔。这些值只能是近似值，因为霉菌在低生长速率下会产生黑色素，并且尽管这种聚合物增加了干重，但它不太可能对维持能量需求有贡献。生物量（在此定义为干重减去黑色素）用于计算更有意义的葡萄糖维持系数（每克生物量每小时0.029克葡萄糖）。在所研究的最高生长速率下，获得了生长速率与葡萄糖利用率之间的非线性关系，这表明霉菌在高生长速率下代谢活动发生了质的变化。霉菌的氧化能力在最高生长速率时最高。这一观察结果表明，在较高生长速率下观察到的底物利用率增加是酶合成增强的反映。通过测定不同生长速率下几种酶的比活性，验证了这一假设。然而，与所有其他测定的酶相反，还原型烟酰胺腺嘌呤二核苷酸磷酸：（受体）氧化还原酶的活性在最低生长速率时最高。
