Back D W, Angel J F
Can J Biochem Cell Biol. 1983 Oct;61(10):1108-13. doi: 10.1139/o83-141.
Rat liver glucose-6-phosphate dehydrogenase and malic enzyme were purified and rabbit serum antibodies were prepared against each enzyme. The activities and quantities of both enzymes in the livers of infant rats were subsequently determined during the weaning period. Glucose-6-phosphate dehydrogenase was present and active in the liver of spontaneously weaned rats on postnatal day 17 and increased from postnatal day 21 onwards. Malic enzyme and its activity were undetectable on postnatal day 17. The latter enzyme was detected on postnatal day 21 and increased rapidly afterwards. These changes occurred sooner and were more pronounced when the rats were weaned prematurely on postnatal day 17, especially when the diet contained sucrose. The activities of both enzymes were highly correlated with the amounts of enzyme protein present throughout the experiment. It appeared that the activities of both enzymes in infant rats were likely to be regulated by altering their synthesis and (or) degradation, rather than by activation of existing proteins, assuming that the latter can be detected by the antibodies employed.
纯化了大鼠肝脏葡萄糖-6-磷酸脱氢酶和苹果酸酶，并针对每种酶制备了兔血清抗体。随后在断奶期测定了幼鼠肝脏中这两种酶的活性和含量。葡萄糖-6-磷酸脱氢酶在出生后第17天的自然断奶大鼠肝脏中存在且有活性，并从出生后第21天起增加。出生后第17天未检测到苹果酸酶及其活性。后一种酶在出生后第21天被检测到，随后迅速增加。当大鼠在出生后第17天提前断奶时，这些变化出现得更早且更明显，尤其是当饮食中含有蔗糖时。在整个实验过程中，这两种酶的活性与酶蛋白的量高度相关。假设后者可以被所用抗体检测到，那么幼鼠中这两种酶的活性似乎可能是通过改变它们的合成和（或）降解来调节的，而不是通过现有蛋白质的激活来调节。
