代谢
在哺乳动物中,木糖醇主要在肝脏中被代谢,通过木糖醇脱氢酶和辅因子NAD被氧化成D-木酮糖。D-木酮糖进一步被磷酸化,并通过木酮糖激酶代谢生成木酮糖5-磷酸(Xu5P),这是糖酵解途径非氧化分支的一个中间产物。据报道,Xu5P通过激活蛋白磷酸酶2A(PP2A)_体外_激活核转运和碳水化合物反应元件结合蛋白(ChREBP)的DNA结合活性。因此,ChREBP的激活在体外上调了生脂酶基因的转录,这可能会刺激肝脏中的脂质生成。
In mammals, xylitol is mainly metabolized in the liver where it is oxidized to D-xylulose by xylitol dehydrogenase and cofactor NAD. D-xyluose is further phosphorylated and metabolized by xylulose kinase to xylulose 5-phosphate (Xu5P), an intermediate of the nonoxidative branch of the pentose phosphate pathway. Xu5P is reported to activate nuclear transport and the DNA-binding activities of carbohydrate response element binding protein (ChREBP) via activation of activation of protein phosphatase 2A (PP2A) _in vitro_. Activation of ChREBP thereby upregulates the gene transcription of lipogenic enzymes in vitro, which may stimulate lipogenesis in the liver.
来源:DrugBank