Chiang Mai Journal of Science

 Ling-Zhi mushroom (Ganoderma lucidum), a famous medicinal mushroom,  was found to produce α-galactosidase. Fruiting bodies of G. Lucidum strain L₆ were extracted with phosphate-buffered saline in the ratio of 1g :5 ml then the crude extract was assayed for α-galactosidase activity by hydrolysis of p-nitrophenyl-α-D-galactopyranoside. During development of the fruiting body, the hightest activity of the α-galactosidase was obtained in the second week in an amount of 402 mU/ml with specific activity of 202 mU/mg protein. Then the enzyme activity gradually decreased to half of this amount by the seventh week. The enzyme showed optimum activity at pH 6.0 and was stable between pH 4 and 8. The optimum temperature of the enzyme was 70 °C and half of the enzyme activity remained after 1 hour at 78 °C . The α-galactosidase activity was strongly inhibited by Ag⁺, Hg⁺⁺, p-chloromercuribenzoate and galactose. When p-nitrophenyl-α-D-galactopyranoside was incubated with the enzyme, two oligosaccharides were detected by HPLC. This indicated the enzymen catalyzed a transgalactosylation reaction.