| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1952654 | Biochimie | 2011 | 6 Pages |
Jack bean α-mannosidase (JBM) is a well-studied plant vacuolar α-mannosidase, and is widely used as a tool for the enzymatic analysis of sugar chains of glycoproteins. In this study, the JBM digestion profile of hybrid-type N-glycans was examined using pyridylamino (PA-) sugar chains. The digestion efficiencies of the PA-labeled hybrid-type N-glycans Manα1,6(Manα1,3)Manα1,6(GlcNAcβ1,2Manα1,3)Manβ1,4GlcNAcβ1,4GlcNAc-PA (GNM5-PA) and Manα1,6(Manα1,3)Manα1,6(Galβ1,4GlcNAcβ1,2Manα1,3)Manβ1,4GlcNAcβ1,4GlcNAc-PA (GalGNM5-PA) were significantly lower than that of the oligomannose-type N-glycan Manα1,6(Manα1,3)Manα1,6Manβ1,4GlcNAcβ1,4GlcNAc-PA (M4-PA), and the trimming pathways of GNM5-PA and GalGNM5-PA were different from that of M4-PA, suggesting a steric hindrance to the JBM activity caused by GlcNAcβ1-2Man(α) residues of the hybrid-type N-glycans. We also found that the substrate preference of JBM for the terminal Manα1–6Man(α) and Manα1–3Man(α) linkages in the hybrid-type N-glycans was altered by the change in reaction pH, suggesting a pH-dependent change in the enzyme–substrate interaction.
Research highlights► Jack bean α-mannosidase digestion profile was tested using pyridylaminated N-glycans. ► Digestion efficiency of hybrid-type N-glycans was lower than oligomannose N-glycans. ► The GlcNAcβ1–2Man(α) residue in hybrid-type N-glycans may cause a steric hindrance. ► Substrate preference to the hybrid-type N-glycans was affected by the reaction pH.
