ABSTRACT
Objective: To investigate the enzymatic hydrolysis of gypenosides by β-glucanase 26130 CN to prepare some hydrolyzed secondary saponins, so as to provide material basis for further biological studies. Methods: Using β-glucanase 26130 CN, the total saponins from Herba Gynostemmatis were hydrolyzed with the enzyme catalysis, and the hydrolytic products were analyzed by ultra high- performance liquid chromatography coupled with quadrupole time- of- flight mass spectrometry(UHPLC- Q- TOF/MSE)to identify the converted products. Then, the main components of Herba Gynostemmatis, gypenosides XLIX and A, were used as substrates of the β-glucanase 26130 CN for convertsion to secondary saponin products. The products were separated by preparative highperformance liquid chromatography(HPLC)and identified by NMR and MS. Results: Twenty eight triterpenoid saponins were identified in the total saponin hydrolysate on the basis of their high-resolution MS data, by comparison with the data in the literature, and seven of them were validated to be the converted products. It was found that the β-glucanase 26130 CN could hydrolyze the glycosidic bond of terminal glucose or xylose in the molecule of gypenosides. By the enzymatic hydrolysis of gypenoside XLIX and gypenoside A, gypenoside I(the one glucosyl-lost gypenoside XLIX)and gypenoside UL1(the one xylosyl-lost gypenoside A)were obtained via the preparative HPLC separation of the gypenoside XLIX and gypenoside A hydrolysates, respectively. Conclusion: β-glucanase 26130 CN could effectively catalyze the hydrolysis of terminal glucosyl and xylosyl groups in gypenosides, with a relatively high hydrolytic conversion rate, which could be used to prepare some secondary saponins or aglycones.
ABSTRACT
1,3-1,4-β-glucanase (E.C.3.2.1.73) is an important industrial enzyme which cleave β-glucans into oligosaccharides through strictly cutting the β-1,4 glycosidic bonds in 3-O-substituted glucopyranose units. Microbial 1,3-1,4-β-glucanase belongs to retaining glycosyl hydrolases of family 16 with a jellyroll β-sandwich fold structure. The present paper reviews the industrial application and protein engineering of microbial β-glucanases in the last decades and forecasts the research prospects of microbial β-glucanases.
Subject(s)
Amino Acid Sequence , Glycoside Hydrolases , Models, Molecular , Protein Engineering , Substrate SpecificityABSTRACT
Objective Enzymatic hydrolysis of Astragali Radix polysaccharides from different germplasm resources Astragalusmembranaceus var. mongholicus (MG) (cultured and natural) or Astragalusmembranaceus (MJ) (cultured and natural) was carried out by the best enzymolysis conditions of endo-1,3-β-glucanase. Saccharide fingerprints were obtained for the identification and evaluation of the germplasm resources of Astragali Radix by Fluorophore-assisted Carbohydrate Electrophoresis (FACE). Methods The data were analyzed by principal component analysis and t test using SMICA software to distinguishdifferential sugar segments among different germplasm resources of Astragali Radix. Results Pentasaccharide and hexasaccharide of endo-1,3-β-glucanasehydrolyzate could be used as differentiated saccharide fragments between natural MG and MJ.Trisaccharide, tetrasaccharide, and pentasaccharide could be used as differentiated saccharide fragments to distinguish the cultured MG and MJ.The pentasaccharide and hexasaccharide can be used as differential fragments to distinguish MJ (culturedandnatural). Conclusion Thepolysaccharide products degraded by endo-1,3-β-glucanase can well distinguish Astragali Radix species (MG and growth mode (cultured and natural Astragali Radix). This study laid the foundation for the quality evaluation of Astragali Radix and screening of active oligosaccharides.
ABSTRACT
Objective To prepare an active anti-tumor component, compound K (C-K), from saponins in leaves of Panax notoginseng (SLPN) using immobilized β-glucanase. Methods Two entrapments, alginate gel-1 (Alg 1) and alginate gel-2 (Alg 2), were evaluated for their ability to immobilize β-glucanase. The amount and purity of C-K obtained from the transformation process were analyzed by HPLC, and the immobilizing parameters were optimized. Results β-Glucanase can be immobilized and reused with either of the entrapment. However, using AIg 1 resulted in higher enzyme activity than Alg 2. The optimal concentration of the immobilized enzyme was 10%; The optimal crosslinking time was 4-6 h; and the optimal concentration of the crosslinking agent was 6%-7%. Conclusion Immobilized β-glucanase shows sustained enzyme activity, good ethanol tolerance, and was reusable for the preparation of C-K from SLPN.