Hydrolyzes the short-chain alpha-galactosaccharides raffinose, melibiose and stachyose. Hydrolysis of terminal, non-reducing alpha-D-galactose residues in alpha-D-galactosides, including galactose oligosaccharides, galactomannans and galactolipids. Inhibited by hydrolyzation product alpha-galactopyranose and to a lesser extent by beta-galactopyranose, its mutarotational product (PubMed:26005928). Inhibited by synthetic cyclopropyl carbasugars (PubMed:27783466). kcat is 176 s(1) for p-nitrophenol-alpha-galactoside (at pH 5.0 and 75 degrees Celsius). kcat is 109 s(1) for raffinose (at pH 5.0 and 75 degrees Celsius) (PubMed:9741105). kcat is 8 s(1) for p-nitrophenyl-alpha-D-galactopyranoside (at pH 5.0 and 37 degrees Celsius) (PubMed:24237145). kcat is 2.33 s(1) for melibiose (at pH 5.0 and 37 degrees Celsius). kcat is 5.0 s(1) for raffinose (at pH 5.0 and 37 degrees Celsius). kcat is 0.53 s(1) for stachyose (at pH 5.0 and 37 degrees Celsius) (PubMed:25486100). Optimum pH is 5.0-5.5 when using synthetic substrate p-nitrophenyl-alpha-D-galactopyranoside. Optimum temperature is 90-95 degrees Celsius when using synthetic substrate p-nitrophenyl-alpha-D-galactopyranoside. The half-life of thermoinactivation is 6.5 h at 85 degrees Celsius. Homodimer. Belongs to the glycosyl hydrolase 36 family.