Reaction: Hydrolysis of β-L-Arap-(1→3)-L-Araf disaccharides from non-reducing terminals in branches of type II arabinogalactan attached to proteins.
Glossary: Araf = arabinofuranose
Arap = arabinopyranose
Other name(s): 3-O-β-L-arabinopyranosyl-α-L-arabinofuranosidase; AAfase
Systematic name: type II arabinogalactan exo α-(1,3)-[β-L-arabinopyranosyl-(1→3)-L-arabinofuranose] hydrolase (non-reducing end)
Comments: The enzyme, characterized from the bacterium Bifidobacterium pseudocatenulatum, specifically hydrolyses β;-L-Arap-(1→3)-L-Araf disaccharides from the non-reducing terminal of arabinogalactan using an exo mode of action. It is active with arabinogalactan-proteins (AGPs) containing type II arabinogalactans such as gum arabic AGP and larch AGP. The enzyme can also hydrolyse α-D-Galp-(1→3)-L-Araf disaccharides (cf. EC 3.2.1.215) with a much lower activity.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
References:
1. Sasaki, Y., Yanagita, M., Hashiguchi, M., Horigome, A., Xiao, J. Z., Odamaki, T., Kitahara, K. and Fujita, K. Assimilation of arabinogalactan side chains with novel 3-O-β-L-arabinopyranosyl-α-L-arabinofuranosidase in Bifidobacterium pseudocatenulatum. Microbiome Res. Rep. 2 (2023) 12.