Purification and Substrate Specificity of AGinkgo bilobaGlycosidase Active in β-1,2-Xylosidic Linkage in Plant Complex TypeN-Glycans

Abstract

The β-xylosidase, which is active against plant complex type N-glycans, was purified to homogeneity from Ginkgo biloba seeds. The N-terminal amino acid sequence, G-S-A-A-G-N-R-, of the Ginkgo β-xylosidase (β-Xyl'ase Gb) was consistent with the deduced internal amino acid sequence of an Arabidopsis β-xylosidase (AtBXL1). β-Xyl'ase Gb hydrolyzed the β1-2 xylosyl residue from Xylβ1-2Manβ1-4GlcNAcβ1-4GlcNAc-PA and Xylβ1-2Manβ1-4GlcNAcβ1-4(Fucα1-3)GlcNAc-PA, but not that from Manα1-6(Manα1-3)(Xylβ1-2)Manβ1-4GlcNAcβ1-4(Fucα1-3)GlcNAc-PA.

β-Galactosidase from Ginkgo biloba seeds active against β-galactose-containing N-glycans: purification and characterization

“…In our previous report, 28) we purified and characterized a β-xylosidase from Ginkgo biloba seeds (β-Xyl'ase Gb-1), which hydrolyzed the β1-2 xylose linkage in truncated-type plant N-glycan (Xyl 1 Man 1 -Fuc 1 GlcNAc 2 or Xyl 1 Man 1 GlcNAc 2 ). In the course of purification of β-Xyl'ase Gb, we screened several exoglycosidase activities (α-fucosidase, α-mannosidase, 29) and β-galactosidase) and confirmed that G. biloba seeds exhibited some of β-Gal'ase's activities, suggesting that Ginkgo seed would be a good material to purify or identify the β-Gal'ase(s) responsible for the degradation of β-galactosylated N-glycans.…”