Banerjee M, Kumar H D
Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, India.
Ecotoxicol Environ Saf. 1990 Oct;20(2):203-10. doi: 10.1016/0147-6513(90)90059-e.
The effect of pyruvate on nitrogenase activity in the N2-fixing cyanobacterium Aulosira fertilissima has been studied. Addition of 0.01-1.0 mM concentrations of pyruvate to actively N2-fixing cultures stimulated the enzyme activity in light; the maximum stimulation was observed with 0.3 mM pyruvate. There was no detectable stimulation of nitrogenase activity in the dark. Addition of pyruvate had no effect on the growth rate. DCMU gradually inhibited nitrogenase activity, but supplementation of 0.3 mM pyruvate to such cultures restored normal activity. Furthermore, pyruvate-induced stimulation of nitrogenase activity was found to be stimulated by anaerobic conditions. The inactivation of nitrogenase activity by the addition of O2 was restored by pyruvate. From 14CO2 uptake studies it appears that the alga preferred to take up pyruvate even in the presence of 14CO2. Thus it appears that pyruvate is taken up and metabolized by the alga, which manifests the observed effects.
已对丙酮酸对固氮蓝藻费氏织线藻中固氮酶活性的影响进行了研究。向积极进行固氮的培养物中添加0.01 - 1.0 mM浓度的丙酮酸，在光照下会刺激该酶的活性；在添加0.3 mM丙酮酸时观察到最大刺激效果。在黑暗中未检测到对固氮酶活性的刺激作用。添加丙酮酸对生长速率没有影响。二氯苯基二甲基脲（DCMU）会逐渐抑制固氮酶活性，但向此类培养物中补充0.3 mM丙酮酸可恢复正常活性。此外，发现丙酮酸诱导的固氮酶活性刺激作用在厌氧条件下会增强。添加氧气导致的固氮酶活性失活可被丙酮酸恢复。从14CO2吸收研究来看，即使存在14CO2，该藻类似乎也更倾向于吸收丙酮酸。因此，似乎该藻类会吸收并代谢丙酮酸，从而表现出所观察到的效果。
