Involved in the degradation of arabinan and is a key enzyme in the complete degradation of the plant cell wall. Catalyzes only the cleavage of terminal alpha-(1->5) arabinofuranosyl bonds of arabinan present in the arabinofuranosyl polysaccharides or oligosaccharides. It cannot act on other arabinose-containing polysaccharides and arabinoxylo-oligosaccharides. Hydrolysis of terminal non-reducing alpha-L-arabinofuranoside residues in alpha-L-arabinosides. kcat is 6.5 min(-1) with p-nitrophenyl-alpha-L-arabinofuranoside as substrate. Optimum pH is 6.0. Stable from pH 5.0 to pH 6.5. Optimum temperature is 45 degrees Celsius. Glycan metabolism; L-arabinan degradation. Organized into two domains: an N-terminal catalytic domain and a C-terminal arabinose-binding domain (ABD). Belongs to the glycosyl hydrolase 43 family.