Reaction: Endohydrolysis of (1→6)-β-D-galactosidic linkages in arabinogalactan proteins and (1→3):(1→6)-β-galactans to yield galactose and (1→6)-β-galactobiose as the final products
Other name(s): endo-1,6-β-galactanase; endo-β-(1→6)-galactanase
Comments: The enzyme specifically hydrolyses 1,6-β-D-galactooligosaccharides with a degree of polymerization (DP) higher than 3, and their acidic derivatives with 4-O-methylglucosyluronate or glucosyluronate groups at the non-reducing terminals [2]. 1,3-β-D- and 1,4-β-D-galactosyl residues cannot act as substrates. The enzyme can also hydrolyse α-L-arabinofuranosidase-treated arabinogalactan protein (AGP) extracted from radish roots [2,3]. AGPs are thought to be involved in many physiological events, such as cell division, cell expansion and cell death [3].
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:
References:
1. Brillouet, J.-M., Williams, P. and Moutounet, M. Purification and some properties of a novel endo-β-(1→6)-D-galactanase from Aspergillus niger. Agric. Biol. Chem. 55 (1991) 1565-1571.
2. Okemoto, K., Uekita, T., Tsumuraya, Y., Hashimoto, Y. and Kasama, T. Purification and characterization of an endo-β-(1→6)-galactanase from Trichoderma viride. Carbohydr. Res. 338 (2003) 219-230. [PMID: 12543554]
3. Kotake, T., Kaneko, S., Kubomoto, A., Haque, M.A., Kobayashi, H. and Tsumuraya, Y. Molecular cloning and expression in Escherichia coli of a Trichoderma viride endo-β-(1→6)-galactanase gene. Biochem. J. 377 (2004) 749-755. [PMID: 14565843]