小肠黏膜中的葡萄糖代谢。磷酸戊糖途径的酶。

Glucose metabolism in the mucosa of the small intestine. Enzymes of the pentose phosphate pathway.

Srivastava L M, Hübscher G

Biochem J. 1966 Oct;101(1):48-55. doi: 10.1042/bj1010048.

Abstract

The occurrence of five enzymes of the pentose phosphate pathway in cell-free preparations of the mucosa of rat small intestine is described. These enzymes were found to be localized mainly in the supernatant fraction (6240000g-min.). 2. The properties of glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were studied with respect to K(m) values for substrates and NADP(+), pH optima and the effects of p-chloromercuribenzoate and palmitoyl-CoA. Higher total and specific activities of these two dehydrogenases were noted in the proximal half of the small intestine of the rat than in the distal half. 3. The specific activities of glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase in the mucosa of the small intestine of the rat, cat, rabbit and guinea pig were compared. 4. In the rat the specific activities of ribose 5-phosphate isomerase, transketolase and transaldolase were higher in the supernatant fractions from the intestinal mucosa than in those from the liver. 5. The role of the pentose phosphate pathway is discussed in relation to the metabolism of hexose phosphates in the intestinal mucosa.

摘要

本文描述了大鼠小肠黏膜无细胞制剂中戊糖磷酸途径的五种酶的存在情况。发现这些酶主要定位于上清液部分（6240000g-分钟）。2. 研究了葡萄糖6-磷酸脱氢酶和6-磷酸葡萄糖酸脱氢酶关于底物和NADP⁺的米氏常数、最适pH以及对氯汞苯甲酸和棕榈酰辅酶A的影响。大鼠小肠近端的这两种脱氢酶的总活性和比活性高于远端。3. 比较了大鼠、猫、兔和豚鼠小肠黏膜中葡萄糖6-磷酸脱氢酶和6-磷酸葡萄糖酸脱氢酶的比活性。4. 在大鼠中，小肠黏膜上清液部分的核糖5-磷酸异构酶、转酮醇酶和转醛醇酶的比活性高于肝脏上清液部分。5. 讨论了戊糖磷酸途径在小肠黏膜中己糖磷酸代谢方面的作用。