Substrate specificities of alpha-galactosidases from yeasts.

Twenty-nine strains of yeasts, which are capable of using galactose, melibiose, or raffinose, were screened for alpha-galactosidase production. Among the strains, 5 produced intracellular and extracellular alpha-galactosidases, and 2 produced only intracellular enzyme. Substrate specificities of these enzymes were explored using 6(3)-alpha-D-galactosyl-1,4-beta-D-mannotriose and 6(3)-alpha-D-galactosyl-1,4-beta-D-mannotetraose. All enzymes liberated the terminal galactose from 6(3)-alpha-D-galactosyl-1,4-beta-D-mannotriose, but did not the stub galactose from 6(3)-alpha-D-galactosyl-1,4-beta-D-mannotetraose.