Activity of an Aspergillus terreus α-arabinofuranosidase on phenolic-substituted oligosaccharides

The effect of phenolic substitutions on the activity of an α-arabinofuranosidase from Aspergillus terreus was investigated using feruloylated oligosaccharides isolated from plant cell walls, equivalent oligosaccharides obtained through treatment with specific ferulic acid esterases, and a synthetic lignin-carbohydrate complex (LCC). Feruloyl substituents limited the hydrolysis of arabinoxylan and arabinan oligosaccharides but only if the feruloyl group was esterified to the terminal non-reducing arabinose. Somewhat surprisingly, the LCC-model compound, in which the arabinose residue is substituted with a bulky dilignol group, was degraded by the enzyme. This indicated that the enzyme is able to approach this linkage from the xylose side.