• Journal of Microbiology and Biotechnology
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• v.21 no.10
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• pp.1057-1063
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• 2011

Herein, a novel ginsenosidase, named ginsenosidase type IV, hydrolyzing 6-O-multi-glycosides of protopanaxatriol-type ginsenosides (PPT), such as Re, R1, Rf, and Rg2, was isolated from the Aspergillus sp. 39g strain, purified, and characterized. Ginsenosidase type IV was able to hydrolyze the 6-O-${\alpha}$-L-($1{\rightarrow}2$)-rhamnoside of Re and the 6-O-${\beta}$-D-($1{\rightarrow}2$)-xyloside of R1 into ginsenoside Rg1. Subsequently, it could hydrolyze the 6-O-${\beta}$-D-glucoside of Rg1 into F1. Similarly, it was able to hydrolyze the 6-O-$_{\alpha}$-L-($1{\rightarrow}2$)-rhamnoside of Rg2 and the 6-O-${\beta}$-D-($1{\rightarrow}2$)-glucoside of Rf into Rh1, and then further hydrolyze Rh1 into its aglycone. However, ginsenosidase type IV could not hydrolyze the 3-O- or 20-O-glycosides of protopanaxadiol-type ginsenosides (PPD), such as Rb1, Rb2, Rb3, Rc, and Rd. These exhibited properties are significantly different from those of glycosidases described in Enzyme Nomenclature by the NC-IUBMB. The optimal temperature and pH for ginsenosidase type IV were $40^{\circ}C$ and 6.0, respectively. The activity of ginsenosidase type IV was slightly improved by the $Mg^{2+}$ ion, and inhibited by $Cu^{2+}$ and $Fe^{2+}$ ions. The molecular mass of the enzyme, based on SDS-PAGE, was noted as being approximately 56 kDa.

• Journal of Microbiology and Biotechnology
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• v.20 no.6
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• pp.1011-1017
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• 2010

A novel dioscin-glycosidase that specifically hydrolyzes multi-glycosides, such as 3-O-${\alpha}$-L-($1{\to}4$)-rhamnoside, 3-O-${\alpha}$-L-($1{\to}2$)-rhamnoside, 3-O-${\alpha}$-L-($1{\to}4$)-arabinoside, and ${\beta}$-D-glucoside, on diosgenin was isolated from the Absidia sp.d38 strain, purified, and characterized. The molecular mass of the new dioscin-glycosidase is about 55 kDa based on SDS-PAGE. The dioscin-glycosidase gradually hydrolyzes either 3-O-${\alpha}$-L-($1{\to}4$)-Rha or 3-O-${\alpha}$-L-($1{\to}2$)-Rha from dioscin into 3-O-${\alpha}$-L-Rha-${\beta}$-D-Glc-diosgenin, further rapidly hydrolyzes the other ${\alpha}$-L-Rha from 3-O-${\alpha}$-L-Rha-${\beta}$-D-Glc-diosgenin into the main intermediate products of 3-O-${\beta}$-D-Glc-diosgenin, and subsequently hydrolyzes these intermediate products into aglycone as the final product. The enzyme also gradually hydrolyzes 3-O-${\alpha}$-L-($1{\to}4$)-arabinoside, 3-O-${\alpha}$-L-($1{\to}2$)-rhamnoside, and ${\beta}$-D-glucoside from [3-O-${\alpha}$-L-($1{\to}4$)-Ara, 3-O-${\alpha}$-L-($1{\to}4$)-Rha]-${\beta}$-D-Glc-diosgenin into diosgenin as the final product, exhibiting significant differences from previously reported glycosidases. The optimal temperature and pH for the new dioscin-glycosidase is $40^{\circ}C$ and 5.0, respectively. Whereas the activity of the new dioscin-glycosidase was not affected by $Na^+$, $K^+$, and $Mg^{2+}$ ions, it was significantly inhibited by $Cu^{2+}$ and $Hg^{2+}$ ions, and slightly affected by $Ca^{2+}$ ions.