Absence of glucose uptake by liver microsomes: an explanation for the complete latency of glucose dehydrogenase.
Absence of glucose uptake by liver microsomes: an explanation for the complete latency of glucose dehydrogenase.
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肝微粒体缺乏葡萄糖摄取：葡萄糖脱氢酶完全潜伏期的解释。
DOI：
10.1006/bbrc.1994.1619
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发表时间：
1994
影响因子：
3.1
通讯作者：
G. van de Werve
中科院分区：
文献类型：
--
作者：
A. Romanelli;J. St;H. Vidal;S. Tchu;G. van de Werve
研究了大鼠肝微粒体对葡萄糖的渗透性与己糖-6-磷酸脱氢酶系统的关系（EC 1.1.1.47）。结果发现，无论是未处理的微粒体还是经洗涤剂处理的微粒体，都可以用NADP作为辅酶来测定葡萄糖-6-磷酸脱氢酶的活性。然而，当葡萄糖用作底物时，活性仅在洗涤剂处理的微粒体中可测量。此外，在各种实验条件下，放射性葡萄糖添加到微粒体中从未被囊泡吸收。我们的研究结果表明，NADP（或NAD）的可用性可能不是在未处理的微粒体中没有葡萄糖脱氢酶活性的原因，而是膜对葡萄糖的不渗透性将解释观察到的完整潜伏期。这一发现需要重新评估葡萄糖转运与内质网其他酶（例如葡萄糖-6-磷酸酶）的关系。
The permeability of rat liver microsomes to glucose was investigated in relation to the hexose-6-phosphate dehydrogenase system (EC 1.1.1.47). It was found that glucose-6-phosphate dehydrogenase activity could be assayed with NADP as coenzyme in both untreated and detergent-treated microsomes. However, when glucose was used as substrate, activity was only measurable in detergent-treated microsomes. Moreover, radioactive glucose added to microsomes in a variety of experimental conditions was never taken up by the vesicles. Our results indicate that NADP (or NAD) availability is probably not the reason for the absence of glucose dehydrogenase activity in untreated microsomes but rather membrane impermeability to glucose would account for the complete latency observed. This finding calls for a reevaluation of glucose transport in relation to other enzymes of the endoplasmic reticulum, such as glucose-6-phosphatase.