虹鳟（鲑鱼）肝脏中的葡萄糖脱氢酶、6-磷酸葡萄糖脱氢酶和己糖激酶。饥饿和温度变化的影响。

Glucose dehydrogenase, glucose-6-phosphate dehydrogenase and hexokinase in liver of rainbow trout (Salmo gairdneri). Effects of starvation and temperature variations.

Tranulis M A, Christophersen B, Blom A K, Borrebaek B

Department of Biochemistry, Veterinary College of Norway, Oslo.

Comp Biochem Physiol B. 1991;99(3):687-91. doi: 10.1016/0305-0491(91)90355-h.

Abstract

Activities of trout liver glucose dehydrogenase (GDH, EC 1.1.1.47) and glucose-6-phosphate dehydrogenase (G6PD, EC 1.1.1.49) were increased after a sudden drop in water temperature, but not in long-time cold acclimated as compared with warm acclimated trout. 2. Possibly, the activities of GDH and G6PD were temporarily increased in connection with metabolic adaptation to the lower temperature. 3. The activities of GDH and G6PD were not changed by the stress of handling. 4. Partially purified trout liver GDH has a lower activation energy with glucose than with glucose-6-phosphate as substrate, and the Km (glucose) decreases with decreasing assay temperature. 5. At low temperatures, the activity of trout liver GDH with glucose as substrate may be comparable to that of glucose-6-phosphate. 6. Partially purified beef liver GDH has a high activation energy with glucose as substrate, and the Km (glucose) does not change with the assay temperature. 7. Hexokinase (HK, EC 2.7.1.1) and GDH activities were unchanged when trout were deprived of food for 4 weeks. Apparently, the trout liver glucose utilization did not adapt to the starvation.

摘要

水温骤降后，虹鳟鱼肝葡萄糖脱氢酶（GDH，EC 1.1.1.47）和葡萄糖-6-磷酸脱氢酶（G6PD，EC 1.1.1.49）的活性增加，但与暖适应虹鳟相比，长期冷适应的虹鳟其活性并未增加。2. 可能与对较低温度的代谢适应相关，GDH和G6PD的活性暂时增加。3. 处理应激并未改变GDH和G6PD的活性。4. 部分纯化的虹鳟鱼肝GDH以葡萄糖为底物时的活化能低于以葡萄糖-6-磷酸为底物时，并且Km（葡萄糖）随测定温度降低而减小。5. 在低温下，虹鳟鱼肝以葡萄糖为底物时GDH的活性可能与以葡萄糖-6-磷酸为底物时相当。6. 部分纯化的牛肝GDH以葡萄糖为底物时具有较高的活化能，并且Km（葡萄糖）不随测定温度变化。7. 虹鳟禁食4周后，己糖激酶（HK，EC 2.7.1.1）和GDH的活性未改变。显然，虹鳟鱼肝的葡萄糖利用并未适应饥饿状态。