An Organic Solvent-Tolerant α-L-Rhamnosidase from <i>Dictyoglomus thermophilum</i> and Its Application in Production of Icariside I from Icariin
Icariside I, a bioactive flavonoid derivative derived from <i>Herba epimedii</i>, demonstrates better pharmacological properties compared to its precursor icariin. Enzymatic conversion of icariin to icariside I using α-L-rhamnosidase represents an efficient biotechnological approach. In...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-07-01
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| Series: | Molecules |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1420-3049/30/13/2847 |
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| Summary: | Icariside I, a bioactive flavonoid derivative derived from <i>Herba epimedii</i>, demonstrates better pharmacological properties compared to its precursor icariin. Enzymatic conversion of icariin to icariside I using α-L-rhamnosidase represents an efficient biotechnological approach. In this study, we characterized a GH78 family α-L-rhamnosidase from <i>Dictyoglomus thermophilum</i> (<i>Dth</i>Rha) with promising biocatalytic properties. The recombinant <i>Dth</i>Rha displayed optimal activity at 55 °C and pH 6.0, with remarkable thermostability (retaining > 80% activity after 1 h at 45–65 °C) and pH stability (pH 5.0–7.0). The kinetic parameters <i>K</i><sub>m</sub>, <i>k</i><sub>cat</sub> and <i>k</i><sub>cat</sub>/<i>K</i><sub>m</sub> values for pNPR of 0.44 mM, 7.99 s<sup>−1</sup> and 18.16 s<sup>−1</sup> mM<sup>−1</sup>, respectively. Notably, <i>Dth</i>Rha exhibited good organic solvent tolerance, retaining > 50% activity after 4 h in 10% DMSO. Applied in a DMSO cosolvent system, <i>Dth</i>Rha achieved 92.3% conversion of icariin to icariside I within 4 h under optimized conditions. Interestingly, elevating the substrate concentration to 10 mM resulted in a consistently high icariin conversion of 95.8%. The enzymatic hydrolysis method can be applied to the industrial production of Icariside I. Furthermore, <i>Dth</i>Rha not only cleaves the α-1,2 glycosidic bond between glucoside and rhamnoside in compounds like naringin, but also exhibits tolerance to organic solvents, making it suitable for the hydrolysis of other poorly soluble flavonoids. |
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| ISSN: | 1420-3049 |