Hydrolyzes a variety of simple alpha-D-galactoside as well as more complex molecules such as oligosaccharides and polysaccharides. Hydrolysis of terminal, non-reducing alpha-D-galactose residues in alpha-D-galactosides, including galactose oligosaccharides, galactomannans and galactolipids. Expression on xylan is very high, whereas elevated expression levels are also detected on galactose and xylose. Belongs to the glycosyl hydrolase 27 family.