Ghosh D K, Honigberg B M
J Protozool. 1976 Aug;23(3):450-5. doi: 10.1111/j.1550-7408.1976.tb03811.x.
The activities of glucose-6-phosphate dehydrogenase (G-6-PD) (EC No. 1.1.1.49), 6-phosphogluconate dehydrogenase (PGD) (EC No. 1.1.1.44), and isocitrate dehydrogenase (ICD) (EC No. 1.1.1.42) from promastigotes of Leishmania donovani strain 3S grown at 25 C in modified Tobie's (mT) medium and from promastigotes of the 37 C-adapted substrain of this strain cultivated in the mT at 37 C were assayed at 25 and 37 C. At 25 C ICD from both the strain and the substrain had the highest, and PGD, the lowest activity; the activity of G-6-PD was intermediate, but much closer to that of ICD. Irrespective of the temperature of the assay, the activities of G-6-PD and ICD from the 37 C substrain were significantly higher than those of these enzymes from the parental strain; however, the activity of PGD from the 25 C strain was slightly higher than that of this dehydrogenase from the 37 C-adapted stock. No significant activity losses of G-6-PD and ICD from either the strain or the substrain were noted after incubation of the extracts in the presence of 0.25 M sucrose at 37 C for 2 hr. PGD was unstable in such extracts, but it could be rendered stable by the addition of 4 mM 6-phosphogluconate, G-6-PD was the least and ICD the most dependent on Mg2+ ions. In the 15-25 C range, the Q10 values of the enzymes from the 25 C strain were 2.83, 2.5 and 2.63 for G-6-PD, PGD, and ICD, respectively. These values for the respective enzymes in the 25-35 C range were 2.06, 1.67, and 1.62. The Q10 values of the enzymes from the 37 C substrain in the 15-25 C range were 2.06 for G-6-PD, 3.25 for PGD, and 2.77 for ICD; in the 25-35 C range, the corresponding values were 1.67, 1.46, and 1.83. Cultivation of the 37 C substrain at 25 C was accompanied by a drop in G-6-PD and ICD activities.
对杜氏利什曼原虫3S株前鞭毛体（在改良的托比氏（mT）培养基中于25℃培养）以及该菌株的37℃适应亚株前鞭毛体（在mT培养基中于37℃培养）中的葡萄糖-6-磷酸脱氢酶（G-6-PD）（酶委员会编号1.1.1.49）、6-磷酸葡萄糖酸脱氢酶（PGD）（酶委员会编号1.1.1.44）和异柠檬酸脱氢酶（ICD）（酶委员会编号1.1.1.42）的活性，在25℃和37℃下进行了测定。在25℃时，该菌株和亚株的ICD活性最高，PGD活性最低；G-6-PD的活性处于中间水平，但更接近ICD的活性。无论测定温度如何，37℃亚株的G-6-PD和ICD活性均显著高于亲代菌株中这些酶的活性；然而，25℃菌株的PGD活性略高于37℃适应株中该脱氢酶的活性。在提取物于37℃在0.25M蔗糖存在下孵育2小时后，未观察到该菌株或亚株的G-6-PD和ICD有明显的活性损失。PGD在这种提取物中不稳定，但通过添加4mM 6-磷酸葡萄糖酸可使其稳定，G-6-PD对Mg2+离子的依赖性最小，ICD最大。在15 - 25℃范围内，25℃菌株的G-6-PD、PGD和ICD的Q10值分别为2.83、2.5和2.63。在25 - 35℃范围内，这些酶各自的Q10值分别为2.06、1.67和1.62。37℃亚株的G-6-PD、PGD和ICD在15 - 25℃范围内的Q10值分别为2.06、3.25和2.77；在25 - 35℃范围内，相应的值分别为1.67、1.46和1.83。37℃亚株在25℃培养会伴随G-6-PD和ICD活性下降。
