McDowell W, Weckbecker G, Keppler D O, Schwarz R T
Biochem J. 1986 Feb 1;233(3):749-54. doi: 10.1042/bj2330749.
The sugar nucleotide analogue UDP-glucosamine was found to function as a sugar donor in microsomal preparations of both chick-embryo cells and rat liver, yielding dolichyl monophosphate glucosamine (Dol-P-GlcN). This was characterized by t.l.c. and retention by DEAE-cellulose. Glucosamine was the only water-soluble product released on mild acid hydrolysis. Dol-P-GlcN did not serve as substrate by transferring its glucosamine moiety to dolichol-linked oligosaccharide. Competition experiments between UDP-[3H]glucose and UDP-glucosamine showed Dol-P-[3H]glucose synthesis to be depressed by 56 or 73% in microsomes from chick-embryo cells and rat liver respectively. The concentrations of the UDP-sugars in this experiment were comparable with those occurring in galactosamine-metabolizing liver. These findings suggest that Dol-P-GlcN, formed as a metabolite of D-galactosamine, may interfere with Dol-P-dependent reactions.
已发现糖核苷酸类似物尿苷二磷酸葡糖胺在鸡胚细胞和大鼠肝脏的微粒体制剂中作为糖供体发挥作用,生成二磷酸多萜醇葡糖胺(Dol-P-GlcN)。通过薄层层析和二乙氨基乙基纤维素保留对其进行了表征。葡糖胺是温和酸水解时释放的唯一水溶性产物。Dol-P-GlcN不能通过将其葡糖胺部分转移至与多萜醇连接的寡糖来作为底物。尿苷二磷酸-[³H]葡萄糖和尿苷二磷酸葡糖胺之间的竞争实验表明,在鸡胚细胞和大鼠肝脏的微粒体中,二磷酸多萜醇-[³H]葡萄糖的合成分别被抑制了56%或73%。本实验中尿苷二磷酸糖的浓度与在代谢半乳糖胺的肝脏中出现的浓度相当。这些发现表明,作为D-半乳糖胺代谢产物形成的Dol-P-GlcN可能会干扰依赖二磷酸多萜醇的反应。