Kametani S, Shiga Y, Akanuma H
Department of Life Science (Chemistry), Graduate School of Arts and Sciences, University of Tokyo, Japan.
Eur J Biochem. 1996 Dec 15;242(3):832-8. doi: 10.1111/j.1432-1033.1996.0832r.x.
A unique anhydrohexulose, 1,5-anhydrofructose (1,5AnFru) has been detected in rat livers. Here we describe a microanalytical method for 1,5AnFru using GC/MS and report results on the distribution and production of 1,5 AnFru in rats. The highest levels of 1,5AnFru were found in the liver (0.43 microgram/g wet tissue) and appreciable amounts were detected in adrenal gland and spleen (0.12 microgram/g and 0.09 microgram/g, respectively). Other organs contained lower amounts while plasma contained virtually no detectable 1,5AnFru. We also demonstrated that 1,5AnFru is produced in the cytosol fraction of rat liver homogenate when an alpha-1,4-glucan or glycogen was added; 1,5AnFru was readily reduced to 1,5-anhydroglucitol with NADPH or at a reduced efficiency with NADH in the presence of a Mono Q chromatographic fraction obtained from the same cytosol preparation. Based on these results, we propose the existence of a third degradation pathway, in addition to the phosphorolytic and hydrolytic reaction sequences, from glycogen to 1,5-anhydroglucitol via 1,5AnFru in mammals. However, the physiological significance of 1,5AnFru and this putative minor glycogenolytic pathway in mammals remains obscure.
在大鼠肝脏中检测到一种独特的脱水己糖，即1,5-脱水果糖（1,5AnFru）。在此，我们描述了一种使用气相色谱/质谱联用技术分析1,5AnFru的微量分析方法，并报告了大鼠体内1,5AnFru的分布及生成情况。发现肝脏中1,5AnFru的含量最高（0.43微克/克湿组织），在肾上腺和脾脏中也检测到了可观的量（分别为0.12微克/克和0.09微克/克）。其他器官中的含量较低，而血浆中几乎检测不到1,5AnFru。我们还证明，当添加α-1,4-葡聚糖或糖原时，大鼠肝脏匀浆的胞质溶胶部分会生成1,5AnFru；在存在从同一胞质溶胶制剂中获得的Mono Q色谱级分的情况下，1,5AnFru能被NADPH迅速还原为1,5-脱水葡糖醇，而被NADH还原的效率较低。基于这些结果，我们提出，除了磷酸解和水解反应序列外，在哺乳动物中还存在从糖原经1,5AnFru到1,5-脱水葡糖醇的第三条降解途径。然而，1,5AnFru以及这条推测的次要糖原分解途径在哺乳动物中的生理意义仍不清楚。
