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. Expressed on galactose and galactosecontaining oligosaccharides (lactose, melibiose, raffinose, and stachyose) and polysaccharides (pectin, xylan, gum arabic, gum karaya, and locust bean gum). A C-terminal Ser/Thr-rich region may provide possible sites for O-glycosylation. Belongs to the glycosyl hydrolase 27 family. It is uncertain whether Met-1 or Met-9 is the initiator.