ABSTRACTGerminating seeds ofCassia sericeaSw. contain two molecular forms of α‐galactosidase which were partially purified and characterized. Both enzyme forms had an optimum pH of 5.0 and an optimum temperature of 50 °C. Kmvalues for the substrate p‐nitrophenyl‐α‐D‐galactoside (PNPG) were 0.91 mM and 1.05 mM for the two forms, and substrate inhibition was observed at high concentrations of PNPG. The two forms of the enzyme had molecular weights of 46,000 and 33,000 by gel filtration. The enzyme forms were inhibited completely by Ag+, Cu2+and Hg2+ions and by p‐chloromercuribenzoate showing that thiol groups are probably involved in catalysis.Both α‐galactosidases hydrolyzed melibiose and raffinose, although hydrolysis of stachyose could not be detected. The enzyme may find potential use in the food industry to hydrolyze flatulence‐causing sugars in processed foods and in production of sucrose from high‐raffinose sugar beets. That the source(C. sericeaseeds) of the enzyme is inexpensive provides an added advantage over use of cultivated legumes as a sour