Purification and Characterization of a Novel Exo-β-1,3-1,6-glucanase from the Fruiting Body of the Edible Mushroom Enoki (Flammulina velutipes)

Abstract

To elucidate the role of β-glucanases in the cell-wall degradation involved in morphogenesis, an exo-β-1,3-1,6-glucanase (FvBGL1) was purified from fruiting bodies of the edible mushroom Enoki (Flammulina velutipes), and its enzymatic properties were studied. At least three β-glucanases were detected in the crude extract by zymogram assay when 1% laminarin was used as substrate. The molecular mass of FvBGL1 was estimated by SDS–PAGE to be 80 kDa. The optimum pH and temperature for the action of FvBGL1 were 6.1 and 60 °C respectively. FvBGL1 was completely inactivated by 1 mM mercuric ions. FvBGL1 hydrolyzed F. velutipes cell-wall β-glucan as well as β-1,3- and β-1,6-glucans from various sources with glucose as the only reaction product. Transglucosylation was observed when the enzyme acted on laminarinonaose. FvBGL1 can be assumed to degrade F. velutipes cell-wall β-1,3-glucan, but most probably acts more efficiently in concert with other endogenous β-glucan degrading enzymes.