Abstract
To investigate the function of amylases in the fruit-body formation of an ectomycorrhizal fungus, Lyophyllum shimeji, we purified the extracellular amylase in the medium of this fungus. The purified enzyme was obtained from 1.7 l stationary culture filtrate, with 4.2% recovery, and showed a single protein band on SDS-PAGE. The molecular mass was about 25 kDa. The enzyme was most active at around 40°C and pH 5.0 and stable over pH 4.5–6.5 for 30 min at 37°C. This amylase was remarkably activated by the presence of Ca2+ ion (7.7 times that of the control), but Ba2+ and Ag+ completely inhibited the activity. The amylase readily hydrolyzed the α-1,4 glucosidic linkage such as dextrin and amylose A (MW, 2900), converting into glucose, and hydrolyzed the α-1,6 glucosidic linkage of isomaltohexaose and amylopectin. However, the enzyme did not hydrolyze the cyclic polysaccharides. On the other hand, when a low molecular mass amylose A was hydrolyzed by this amylase, β-anomer glucose was produced. From these results, we concluded that the amylase from L. shimeji seems to be a glucoamylase.
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Kusuda, M., Ueda, M., Konishi, Y. et al. Characterization of extracellular glucoamylase from the ectomycorrhizal mushroom Lyophyllum shimeji . Mycoscience 45, 383–389 (2004). https://doi.org/10.1007/s10267-004-0196-6
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DOI: https://doi.org/10.1007/s10267-004-0196-6