Promiscuous activity of ER glucosidase II discovered through donor specificity analysis of UGGT

作者：Miyagawa Atsushi^*; Totani Kiichiro; Matsuo Ichiro; Ito Yukishige

来源：Biochemical and Biophysical Research Communications, 2010, 403(3-4): 322-328.

DOI：10.1016/j.bbrc.2010.11.027

• UGGT
• Glucosidase II
• UDP-glucose
• N-glycan
• High-mannose-type

In glycoprotein quality control system in the endoplasmic reticulum (ER), UGGT (UDP-glucose:glycoprotein glucosyltransferase) and glucosidase II (G-II) play key roles. UGGT serves as a glycoprotein folding sensor by virtue of its unique specificity to glucosylate glycoproteins at incompletely folded stage. By using various UDP-Glc analogues, we first analyzed donor specificity of UGGT, which was proven to be rather narrow. However, marginal activity was observed with UDP-galactose and UDP-glucuronic acid as well as with 3-, 4- and 6-deoxy glucose analogues to give corresponding transfer products. Intriguingly, G-II smoothly converted all of them back to Man(9)GlcNAc(2), providing an indication that G-II has a promiscuous activity as a broad specificity hexosidase.

• 出版日期2010-12-17