Enzymatic hydrolysis of astragaloside glycosyl groups for the preparation of astragaloside methylglycosides:
a. Aspergillus niger (Aspegillusniger) in the medium containing 5% malt aqueous leachate, 1% enzyme-producing inducer - astragalus aqueous leachate, stirring and ventilated culture at a temperature of 28 ~ 30 under the condition of 50 ~ 100 hours, centrifugation and removal of bacteria to get the supernatant (containing the enzyme mixture), in the supernatant with 60 ~ 75% saturation of ammonium sulphate precipitation of the enzyme proteins, collection of protein In the supernatant, ammonium sulfate was used to precipitate the enzyme protein with 6075% saturation, and the protein was collected, which was dissolved in 1/10 volume of commonly used acetate buffer (0.02M, pH5.0), or phosphate buffer or Tris buffer, and the ammonium sulfate was removed by dialysis, and the enzyme liquid was removed by centrifugation;
b. Use 50 ml of the above enzyme solution, 3 g of astragalus saponin and 100 ml of acetate buffer (0.02 M, pH 5.0) mixed well, at a temperature of 20 ~ 55 under the condition of the reaction for 6 ~ 24 hours, and then add 1/3 volume of n-butanol to extract the saponin for three times, evaporate under reduced pressure, to get the astragalus saponin crude product. With silica gel column separation method (literature 3) to get 0.5 ~ 0.8 g of astragalus methyl glycosides, astragalus methyl glycosides conversion rate of 60 ~ 90%, compared with the original 3 grams of astragalus saponins directly extracted astragalus methyl glycosides increased by 6 times. The above enzyme solution DEAE-Cellulose ion exchange resin column method and BioRed protein preparation chromatography were used to separate and purify astragaloside methyloside enzyme protein, and the molecular weight of the enzyme was determined by SDS electrophoresis method.
