Abstract
There are many unknown enzymes related to metabolism of plant cell wall polysaccharides. Here, we report a novel α-1,2-fucosidase acting on xyloglucan.
We have discovered endo-β-mannosidase (EBM) as a plant specific endoglycosidase acting on N-glycans of glycoproteins (J. Biol. Chem. 279, 38555 (2004)). EBM located in vacuole is thought to play a role in the metabolism of N-glycans. We found a protein complex consisted of EBM and another protein, and purified this protein complex from lily flowers. This associated-protein is highly homologous to a functionally unknown-protein from plants, and slightly homologous to the fucosidase domain of the bifidus AfcA protein. Substrate specificity analysis of this complex protein revealed that it hydrolyzed the α-1,2-fucosyl linkages at the non-reducing end of the sugar chains including a sugar chain derived from xyloglucan. It is interesting to examine physiological role of this novel α-1,2-fucosidase and the significance of its association with EBM.
