Substrate specificity of three recombinant α-L-arabinofuranosidases from Bifidobacterium adolescentis and their divergent action on arabinoxylan and arabinoxylan oligosaccharides.

Division of Gene Technology, Katholieke Universiteit Leuven, Leuven, Belgium.
Biochemical and Biophysical Research Communications (Impact Factor: 2.28). 10/2010; 402(4):644-50. DOI: 10.1016/j.bbrc.2010.10.075
Source: PubMed

ABSTRACT Bifidobacterium adolescentis possesses several arabinofuranosidases able to hydrolyze arabinoxylans (AX) and AX oligosaccharides (AXOS), the latter being bifidogenic carbohydrates with potential prebiotic properties. We characterized two new recombinant arabinofuranosidases, AbfA and AbfB, and AXH-d3, a previously studied arabinofuranosidase from B. adolescentis. AbfA belongs to glycoside hydrolase family (GH) 43 and removed arabinose from the C(O)2 and C(O)3 position of monosubstituted xylose residues. Furthermore, hydrolytic activity of AbfA was much larger towards substrates with a low amount of arabinose substitutions. AbfB from GH 51 only cleaved arabinoses on position C(O)3 of disubstituted xyloses, similar to GH 43 AXH-d3, making it to our knowledge, the first reported enzyme with this specificity in GH 51. AbfA acted synergistically with AbfB and AXH-d3. In combination with AXH-d3, it released 60% of arabinose from wheat AX. Together with recent studies on other AXOS degrading enzymes from B. adolescentis, these findings allowed us to postulate a mechanism for the uptake and hydrolysis of bifidogenic AXOS by this organism.

  • [Show abstract] [Hide abstract]
    ABSTRACT: The detailed characterization of arabinoxylan-active enzymes, such as double-substituted xylan arabinofuranosidase activity, is still a challenging topic. Ad hoc chromogenic substrates are useful tools and can reveal subtle differences in enzymatic behavior. In this study, enzyme selectivity on natural substrates has been compared with enzyme selectivity towards aryl-glycosides. This has proven to be a suitable approach to understand how artificial substrates can be used to characterize arabinoxylan-active α-l-arabinofuranosidases (Abfs).
    Biochimica et Biophysica Acta (BBA) - General Subjects 07/2014; 1840(10). DOI:10.1016/j.bbagen.2014.07.001 · 3.83 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this study, the impact of structural features of (feruloylated) arabinoxylanoligosaccharides (AXOS) on their fermentability and antioxidant properties during in vitro fermentation was investigated. Two AXOS samples with a low average degree of arabinose substitution, specifically differing in average degree of polymerization, and three AXOS samples, specifically differing in ferulic acid (FA) content and appearance (free or bound), were incubated with cultured human colon microbiota. While the impact of average degree of polymerization on AXOS fermentation was small under the conditions used, both bound and free FA inhibited AXOS fermentation. Bound FA probably hinders enzyme activity sterically. Free FA and its microbial metabolites can exert antibacterial effects. Feruloylated AXOS samples exhibited good antioxidant properties, although the antioxidant activity decreased during fermentation as free or released FA was further metabolized.
    Journal of Functional Foods 09/2014; 10:1–12. DOI:10.1016/j.jff.2014.05.011 · 4.48 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Recent insights into the relationship between the human gut and its resident microbiota have revolutionized our appreciation of this symbiosis and its impact on health and disease development. Accumulating evidence on probiotic and prebiotic interventions has demonstrated promising effects on promoting gastrointestinal health by modulating the microbiota toward the enrichment of beneficial microorganisms. However, the precise mechanisms of how prebiotic nondigestible oligosaccharides are metabolized by these beneficial microbes in vivo remain largely unknown. Genome sequencing of probiotic lactobacilli and bifidobacteria has revealed versatile carbohydrate metabolic gene repertoires dedicated to the catabolism of various oligosaccharides. In this review, we highlight recent findings on the genetic mechanisms involved in the utilization of prebiotic fructooligosaccharides, β-galactooligosaccharides, human milk oligosaccharides, and other prebiotic candidates by these probiotic microbes. Expected final online publication date for the Annual Review of Food Science and Technology Volume 6 is February 28, 2015. Please see for revised estimates.
    Review of Food Science and Technology 12/2014; DOI:10.1146/annurev-food-022814-015706 · 5.98 Impact Factor