The invention relates to a bacterial-derived alpha-L-rhamnosidase
gene,
gene expression and application thereof. A
bacterial strain Enterococcus avium capable of hydrolyzing rhamnetin-3-O-rhamnoside in total flavonoids of
Loranthus tanakae into rhamnetin is screened out, two alpha-L-rhamnosidase genes EaRha1 and EaRha2 in
bacteria are cloned and subjected to
prokaryotic expression, and the target alpha-L-rhamnosidase is obtained. The enzymatic properties of the recombinant proteins EaRha1 and EaRha2 are studied to determine the
hydrolysis mechanism of the two proteins on the
flavonoid compounds, and a theoretical basis and a guiding effect are provided for
biotransformation of the
flavonoid compounds. pNPR is adopted as a substrate, the optimum pH of the recombinant
protein EaRha1 is 7, the optimum temperature is 50 DEG C, and
neohesperidin and
naringin containing alpha-1, 2 glucosidic bonds and
rutin containing alpha-1, 6 glucosidic bonds can be catalytically hydrolyzed by the recombinant
protein EaRha1. Rhamnetin-3-O-rhamnoside is adopted as the substrate, the optimal pH value of the EaRha2 is 7, the optimal temperature is 60 DEG C, and the EaRha2 can hydrolyze rhamnetin-3-O-rhamnoside and
quercitrin.