ABSTRACT
The survival rate of mesenchymal stem cells (MSC), a crucial factor in tissue engineering, is highly dependent on glucose supply. The purpose of this paper is to study the potential of starch foams as glucose suppliers. It is investigated through in vitro hydrolysis by amyloglucosidase in conditions that respect physiological constraints (37 °C and pH 7.4), including a duration of 21 days, and no stirring. Nine extruded starch foams with amylose contents ranging from 0 to 74 %, with various cell wall thicknesses (50 to 300 µm), and different crystallinities (0-30 %) were hydrolysed. These kinetics were fitted by a model which shows that the maximum rate of hydrolysis varies from 7 to 100 %, and which allows the rate of hydrolysis at 21 days to be calculated precisely. The results reveal the major role of amylose in glucose delivery kinetics, and the secondary roles of crystallinity and cell wall thickness of the foams. Additional hydrolysis of starch films revealed that thickness positively influences the amylose chain reorganisation during hydrolysis, which, in slows down and limits glucose delivery. A simple glucose delivery kinetics analysis procedure is proposed to select samples for testing as MSC glucose suppliers.
Subject(s)
Amylose , Biocompatible Materials , Glucose , Mesenchymal Stem Cells , Starch , Hydrolysis , Glucose/chemistry , Starch/chemistry , Biocompatible Materials/chemistry , Amylose/chemistry , Mesenchymal Stem Cells/drug effects , Mesenchymal Stem Cells/metabolism , Mesenchymal Stem Cells/cytology , Kinetics , Glucan 1,4-alpha-Glucosidase/metabolism , Glucan 1,4-alpha-Glucosidase/chemistryABSTRACT
Alpha-glucosidase (maltase, sucrase, isomaltase and glucoamylase) activities which are involved in carbohydrate metabolism are present in human intestinal maltase-glucoamylase (MGAM) and sucrase-isomaltase (SI). Hence, these proteins are important targets to identify drugs against postprandial hyperglycemia thereby for diabetes. To find natural-based drugs against MGAM and SI, Artocarpus heterophyllus leaf was explored for MGAM and SI inhibition in in vitro and in silico. A. heterophyllus leaf aqueous active fraction (AHL-AAF) was prepared using Soxhlet extraction followed by silica column chromatography. The phytoconstituents of AHL-AAF were determined using LC-ESI-MS/MS. AHL-AAF showed dose-dependent and mixed inhibition against maltase (IC50 = 460⯵g/ml; Ki = 300⯵g/ml), glucoamylase (IC50 = 780⯵g/ml; Ki = 480⯵g/ml), sucrase (IC50 = 900⯵g/ml, Ki = 504⯵g/ml) and isomaltase (IC50 = 860⯵g/ml, Ki = 400⯵g/ml). AHL-AAF phytoconstituents interaction with N-terminal (Nt) and C-terminal (Ct) subunits of human MGAM and SI was analyzed using induced-fit docking, molecular dynamics (MD), and binding free energy calculation. In docking studies, rhamnosyl hexosyl methyl quercetin (RHMQ), P-coumaryl-O-16-hydroxy palmitic acid (PCHP), and spirostanol interacted with active site amino acids of human MGAM and SI. Among these RHMQ stably interacted with all the subunits (Nt-MGAM, Ct-MGAM, Nt-SI and Ct-SI) whereas PCHP with Ct-MGAM and Nt-SI during MD analysis. In molecular docking, the docking score of RHMQ with NtMGAM, CtMGAM, NtSI and CtSI was -8.48, -12.88, -11.98 and -11.37â¯kcal/mol. The docking score of PCHP for CtMGAM and NtSI was -8.59 and -8.4â¯kcal/mol, respectively. After MD simulation, the root mean square deviation (RMSD) and root mean square fluctuation (RMSF) values further confirmed the stable protein-ligand interaction. The RMSD value of all the complexes were around 2.5â¯Å and the corresponding RMSF values were also quite low. In MM/GBSA analysis, the involvement of Van der Waals and lipophilic energy in the protein/ligand interactions are understood. Further binding free energy for Nt-MGAM-PCHP, Nt-MGAM-RHMQ, Nt-SI-PCHP, Nt-SI-RHMQ, Ct-MGAM-PCHP, Ct-MGAM-RHMQ and Ct-SI-RHMQ complexes was found to be -24.94, -46.60, -46.56, -44.48, -40.3, -41.86 and -19.39â¯kcal/mol, respectively. Altogether, AHL-AAF showed inhibition of α-glucosidase activities of MGAM and SI. AHL-AAF could be further studied for its effect on diabetes in in vivo.
Subject(s)
Artocarpus , Molecular Docking Simulation , Artocarpus/chemistry , Humans , alpha-Glucosidases/metabolism , alpha-Glucosidases/chemistry , Glycoside Hydrolase Inhibitors/chemistry , Glycoside Hydrolase Inhibitors/pharmacology , Plant Extracts/chemistry , Plant Extracts/pharmacology , Molecular Dynamics Simulation , Glucan 1,4-alpha-Glucosidase/metabolism , Glucan 1,4-alpha-Glucosidase/antagonists & inhibitors , Glucan 1,4-alpha-Glucosidase/chemistry , Plant Leaves/chemistry , Sucrase-Isomaltase Complex/antagonists & inhibitors , Sucrase-Isomaltase Complex/metabolism , Sucrase-Isomaltase Complex/chemistry , Dose-Response Relationship, Drug , Molecular Structure , Structure-Activity Relationship , Animals , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacologyABSTRACT
Food waste is a lucrative source of complex nutrients, which can be transformed into a multitude of bioproducts by the aid of microbial cell factories. The current study emphasizes isolating Glucoamylase enzyme (GA) producing strains that can effectively break down mixed food waste (MW), which serves as a substrate for biomanufacturing. The screening procedure relied heavily on the growth of isolated fungi on starch agar media, to specifically identify the microbes with the highest starch hydrolysis potential. A strain displayed the highest GA activity of 2.9 ± 0.14 U/ml which was selected and identified as Aspergillus fumigatus via molecular methods of identification. Exposure of the A. fumigatus with 200 mM Ethyl methanesulphonate (EMS) led to a 23.79% increase compared to the wild-type GA. The growth conditions like cultivation temperature or the number of spores in the inoculum were investigated. Further, maximum GA activity was exhibited at pH 5, 55 °C, and at 5 mM Ca2+ concentration. The GA showed thermostability, retaining activity even after long periods of exposure to temperatures as high as 95 °C. The improvement of hydrolysis of MW was achieved by Taguchi design where a maximum yield of 0.57 g g-1 glucose was obtained in the hydrolysate. This study puts forth the possibility that mixed food waste, despite containing spices and other microbial growth-inhibitory substances, can be efficiently hydrolyzed to release glucose units, by robust fungal cell factories. The glucose released can then be utilized as a carbon source for the production of value-added products.
Subject(s)
Glucan 1,4-alpha-Glucosidase , Refuse Disposal , Glucan 1,4-alpha-Glucosidase/chemistry , Food Loss and Waste , Food , Fungi , Hydrolysis , Starch , GlucoseABSTRACT
Aspergillus species have been highlighted in enzyme production looking for industrial applications, notably, amylases are one of the most interesting enzymes. They are capable of hydrolyzing α-glycosidic linkages of starch and widely used in industrial processes to produce ethanol, glucose, and fructose syrup as well as in the textiles, detergents, and paper industries applications. In this context, this work aimed at the biochemical characterization of the glucoamylase from Aspergillus japonicus and its application in the bio-bleaching process of recycled paper. The optimum temperature and pH for the glucoamylase assay were standardized as 50°C and 5.5. After 1 h of incubation, glucoamylase retained 90% of its activity at 30-50°C. It also kept 70% of its activity in the pH range of 4.0-6.5 after an hour of incubation. The enzyme led to an increase of 30% in the relative whiteness of 10 dry grams of sulfite paper and magazine paper when applied along with commercial cellulase and 10 mM MnCl2 . In addition, after the treatments, the glucoamylase recovered activity was 30%-32%, which indicates a prolonged availability of the enzyme and can considerably curtail the redundant downstream process of the recycled paper bio-bleaching. Thus, the glucoamylase from A. japonicus has a significant role in bio-bleaching recycled paper, reducing the necessity of hard chemicals, and improving the industrial process in an interesting economic and ecological mode.
Subject(s)
Aspergillus , Glucan 1,4-alpha-Glucosidase , Glucan 1,4-alpha-Glucosidase/chemistry , Temperature , Starch , Hydrogen-Ion ConcentrationABSTRACT
The glucoamylase@ZIF-8 was prepared using ZIF-8 material as the carrier in this study. The preparation process was optimized by response surface methodology, and the stability of glucoamylase@ZIF-8 was determined. The material was characterized by scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The results showed that the optimum preparation process of glucoamylase@ZIF-8 was 1.65 mol 2-methylimidazole, 5.85 mL glucoamylase, 33°C stirring temperature, 90 min stirring time, and 84.0230% ± 0.6006% embedding rate. At 100°C, the free glucoamylase completely lost its activity, whereas the glucoamylase@ZIF-8 still had a retained enzyme activity of 12.0123% ± 0.86158%; at pH 3-6, the highest activity of glucoamylase@ZIF-8 was 95.9531% ± 0.96181%, and about 80% of glucoamylase activity could be retained under alkaline conditions. When the ethanol concentration was 13%, the retained enzyme activity was 7.9316% ± 0.19805%, significantly higher than free enzymes. The Km of glucoamylase@ZIF-8 and free enzyme were 1235.6825 and 80.317 mg/mL, respectively. Vmax was 0.2453 and 0.149 mg/(mL min), respectively. The appearance, crystal strength, and thermal stability of glucoamylase@ZIF-8 were improved after optimization, and they had high reusability.
Subject(s)
Enzymes, Immobilized , Glucan 1,4-alpha-Glucosidase , Enzymes, Immobilized/metabolism , Glucan 1,4-alpha-Glucosidase/chemistry , Glucan 1,4-alpha-Glucosidase/metabolism , Kinetics , X-Ray Diffraction , Enzyme Stability , Hydrogen-Ion Concentration , TemperatureABSTRACT
Glycoside hydrolases (GHs), the enzymes that break glycosidic bonds, are ubiquitous in the ecosystem, where they perform a range of biological functions. As an interesting glycosidase family, Glycoside hydrolase family 97 (GH97) contains α-glucosidase, α-galactosidase, and glucoamylase. Only ten members of GH97 have been characterized so far. It is critical to explore novel members to elucidate the catalytic mechanism and application potential of GH97 family. In this study, a novel glucoamylase QsGH97a from Qipengyuania seohaensis SW-135 was cloned and expressed in E. coli. Sequence analysis and NMR results show that QsGH97a is classified into GH97a, and adopts inverting mechanism. The biochemical characterization indicates that QsGH97a shows the optimal activity at 50 °C and pH 8.0. Ca2+ has little effect on the catalytic activity; however, the activity can be substantially increased by 8-13 folds in the presence of Ba2+ or Sr2+. Additionally, the metal content of QsGH97a assay showed a high proportion of Sr2+. The specific metal activity was initially revealed in glucoamylases, which is not found in other members. These results imply that QsGH97a not only is a new member of GH97, but also has potential for industrial applications. Our study reveals that Ba2+ or Sr2+ may be involved in the catalytic mechanism of glucoamylase, laying the groundwork for a more complete knowledge of GH97 and its possible industrial application.
Subject(s)
Glucan 1,4-alpha-Glucosidase , Strontium , Glucan 1,4-alpha-Glucosidase/chemistry , Barium , Escherichia coli/genetics , Ecosystem , Glycoside Hydrolases/chemistryABSTRACT
To shorten the preparation time of porous starch while simultaneously ensuring its adsorption performance, we treated corn starch with a combination of microwave and complex enzymatic (α-amylase and amyloglucosidase) hydrolysis. Specifically, we investigated the effect of microwave and enzymatic hydrolysis on the structure, physicochemical properties, and adsorption capability of the prepared porous starch. The results showed that the porous starch prepared by combined treatment had denser pores, no new groups were produced in the porous starch, the relative crystallinity, gelatinization temperature, and solubility increased, while the gelatinization enthalpy and swelling power decreased. Compared to enzymatic hydrolysis, the combined treatment yielded starch samples with a larger specific surface area and pore capacity, and the adsorption performance was significantly improved, with water and oil absorption rates increasing from 110.99 % and 133.11 % to 128.29 % and 143.3 %, respectively. These findings indicate that the synergistic processing of microwave and enzymatic hydrolysis has great potential as a productive and rapid method for the preparation of porous starch.
Subject(s)
Microwaves , Starch , Starch/chemistry , Hydrolysis , Porosity , Glucan 1,4-alpha-Glucosidase/chemistryABSTRACT
The requirements for the safety of food products obtained by microbial synthesis are including as obligation for to conduct toxicological studies - the study of various biochemical and immunological markers of toxic effects. The necessity of these studies is explained by a possible change in the structure of food ingredients produced by a microbial cell and, consequently, a change in their biological properties, as well as the possible presence of living forms and/or DNA of producer strains or of their toxic metabolites in these ingredients. At the same time, it is well known that the nutrient composition of foods has a significant impact on the composition and properties of microorganisms that make up the gut microbiome, which, in turn, determines the immune status. The purpose of the research was to justify the analyses of gut microbiocenosis composition for inclusion in the protocol of safety investigation of foods obtained by microbial synthesis [on the example of an enzyme preparation (EP) - a complex of glucoamylase and xylanase from a genetically modified strain of Aspergillus awamori Xyl T-15]. Material and methods. In experimental studies carried out for 80 days, Wistar rats (males and females) were used. The study of the effect of EP (a complex of glucoamylase and xylanase from a genetically modified Aspergillus awamori Xyl T-15 strain) in dozes 10, 100 and 1000 mg/kg body mass on the cecum microbiome and the immune status (content of cytokines and chemokines: IL-1a, IL-4, IL-6, IL-10, IL-17A, INF-γ, TNF-α, MCP-1, MIP-1a and Regulated on Activation Normal T-cell Expressed and Secreted - RANTES) was carried out. Results. It has been shown that EP - a complex of glucoamylase and xylanase from A. awamori Xyl T-15 at doses of 100 mg/kg or more causes mild disturbances in the composition of gut microbiocenosis. At the same time, these disorders have a significant immunomodulat ory and immunotoxic effect on the body, which manifests itself in a dose-dependent change in the profile of pro-inflammatory cytokines and chemokines in blood and spleen. The adverse effect of EP on the body is probably due to the formation of metabolites that are not formed during usual digestive processes in the gastrointestinal tract. The minimum effective dose (LOAEL) of EP was 100 mg/kg body weight In accordance with established requirements, the activity of the EP should not appear in ready-to-use food. Subject to this requirement, amount of EP entering the body cannot exceed the established LOAEL level. Therefore, a complex of glucoamylase and xylanase can be used in food industry, subject to the establishment of regulations «for technological purposes¼ for A. awamori Xyl T-15 strain. Conclusion. The data obtained on the relationship between the state of the microbiome and the immune status upon the introduction of EP indicate the need to include indicators of the state of gut microbiocenosis in the test protocol of safety.
Subject(s)
Aspergillus , Glucan 1,4-alpha-Glucosidase , Animals , Aspergillus/genetics , Aspergillus/metabolism , Cytokines/metabolism , Glucan 1,4-alpha-Glucosidase/chemistry , Glucan 1,4-alpha-Glucosidase/genetics , Glucan 1,4-alpha-Glucosidase/metabolism , Male , Rats , Rats, WistarABSTRACT
Multiple-enzyme cooperation simultaneously is an effective approach to biomass conversion and biodegradation. The challenge, however, lies in the interference of the involved enzymes with each other, especially when a protease is needed, and thus, the difficulty in reusing the enzymes; while extracting/synthesizing new enzymes costs energy and negative impact on the environment. Here, we present a unique approach to immobilize multiple enzymes, including a protease, on a metal-organic material (MOM) via co-precipitation in order to enhance the reusability and sustainability. We prove our strategy on the degradation of starch-containing polysaccharides (require two enzymes to degrade) and food proteins (require a protease to digest) before the quantification of total dietary fiber. As compared to the widely adopted "official" method, which requires the sequential addition of three enzymes under different conditions (pH/temperature), the three enzymes can be simultaneously immobilized on the surface of our MOM crystals to allow for contact with the large substrates (starch), while MOMs offer sufficient protection to the enzymes so that the reusability and long-term storage are improved. Furthermore, the same biodegradation can be carried out without adjusting the reaction condition, further reducing the reaction time. Remarkably, the simultaneous presence of all enzymes enhances the reaction efficiency by a factor of â¼3 as compared to the official method. To our best knowledge, this is the first experimental demonstration of using aqueous-phase co-precipitation to immobilize multiple enzymes for large-substrate biocatalysis. The significantly enhanced efficiency can potentially impact the food industry by reducing the labor requirement and enhancing enzyme cost efficiency, leading to reduced food cost. The reduced energy cost of extracting enzymes and adjusting reaction conditions minimize the negative impact on the environment. The strategy to prevent protease damage in a multi-enzyme system can be adapted to other biocatalytic reactions involving proteases.
Subject(s)
Amylases/chemistry , Biomass , Enzymes, Immobilized/chemistry , Glucan 1,4-alpha-Glucosidase/chemistry , Metal-Organic Frameworks/chemistry , Peptide Hydrolases/chemistry , Biocatalysis , Hydrolysis , Proof of Concept Study , Proteins/chemistry , Starch/chemistryABSTRACT
Enzymes immobilized on a nano-structured surface were used to switch the activity of one enzyme by a local pH change produced by another enzyme. Immobilized amyloglucosidase (AMG) and trypsin were studied as examples of the pH-dependent switchable "target enzymes." The reactions catalyzed by co-immobilized urease or esterase were increasing or decreasing the local pH, respectively, thus operating as "actuator enzymes." Both kinds of the enzymes, producing local pH changes and changing biocatalytic activity with the pH variation, were orthogonal in terms of the biocatalytic reactions; however, their operation was coupled with the local pH produced near the surface with the immobilized enzymes. The "target enzymes" (AMG and trypsin) were changed reversibly between the active and inactive states by applying input signals (urea or ester, substrates for the urease or esterase operating as the "actuator enzymes") and washing them out with a new portion of the background solution. The developed approach can potentially lead to switchable operation of several enzymes, while some of them are inhibited when the others are activated upon receiving external signals processed by the "actuator enzymes." More complex systems with branched biocatalytic cascades can be controlled by orthogonal biocatalytic reactions activating selected pathways and changing the final output.
Subject(s)
Carboxylic Ester Hydrolases/chemistry , Enzymes, Immobilized/chemistry , Glucan 1,4-alpha-Glucosidase/chemistry , Trypsin/chemistry , Urease/chemistry , Animals , Aspergillus niger/enzymology , Biocatalysis , Canavalia/enzymology , Cattle , Enzyme Assays , Hydrogen-Ion Concentration , Nanoparticles/chemistry , Silicon Dioxide/chemistry , SwineABSTRACT
This study describes for the first time the purification and characterization of a glucoamylase from Aspergillus wentii (strain PG18), a species of the Aspergillus genus Cremei section. Maximum enzyme production (â¼3.5 U/ml) was obtained in submerged culture (72 h) with starch as the carbon source, at 25°C, and with orbital agitation (100 rpm). The enzyme was purified with one-step molecular exclusion chromatography. The 86 kDa purified enzyme hydrolyzed starch in a zymogram and had activity against p-nitrophenyl α- d-glucopyranoside. The optimal enzyme pH and temperature were 5.0 and 60°C (at pH 5.0), respectively. The Tm of the purified enzyme was 60°C, at pH 7.0. The purified glucoamylase had a KM for starch of 1.4 mg/ml and a Vmax of 0.057 mg/min of hydrolyzed starch. Molybdenum activated the purified enzyme, and sodium dodecyl sulfate inhibited it. A thin layer chromatography analysis revealed glucose as the enzyme's main starch hydrolysis product. An enzyme's peptide sequence was obtained by mass spectrometry and used to retrieve a glucoamylase within the annotated genome of A. wentii v1.0. An in silico structural model revealed a N-terminal glycosyl hydrolases family 15 (GH15) domain, which is ligated by a linker to a C-terminal carbohydrate-binding module (CBM) from the CBM20 family.
Subject(s)
Aspergillus/enzymology , Aspergillus/metabolism , Glucan 1,4-alpha-Glucosidase/chemistry , Glucan 1,4-alpha-Glucosidase/metabolism , Aspergillus/genetics , Chromatography, Gel , Chromatography, Thin Layer , Computer Simulation , Genome, Fungal , Glucan 1,4-alpha-Glucosidase/analysis , Glucan 1,4-alpha-Glucosidase/genetics , Hydrogen-Ion Concentration , Hydrolysis , Kinetics , Starch/metabolism , Substrate Specificity , TemperatureABSTRACT
Biocatalytic activity of amyloglucosidase (AMG), immobilized on superparamagnetic nanoparticles, is dynamically and reversibly activated or inhibited by applying a magnetic field. The magnetic field triggers aggregation/deaggregation of magnetic particles that are also functionalized with urease or esterase enzymes. These enzymes produce a local pH change in the vicinity of the particles changing the AMG activity.
Subject(s)
Glucan 1,4-alpha-Glucosidase/metabolism , Biocatalysis , Enzymes, Immobilized/chemistry , Enzymes, Immobilized/metabolism , Glucan 1,4-alpha-Glucosidase/chemistry , Hydrogen-Ion Concentration , Magnetic Fields , Nanoparticles/chemistry , Nanoparticles/metabolism , Particle Size , Surface PropertiesABSTRACT
To obtain porous starch granules with higher absorption capacities, three types of enzyme combinations were adopted to modify wheat and maize starches: (1) sequential α-amylase (AA) â glucoamylase (GA); (2) sequential branching enzyme (BE) â GA; and (3) sequential AAâBEâGA. The results indicated that AAâBEâGA treatment had a most optimal influence on porous starches. Compared to AAâGA and BEâGA, the mesopores in wheat starch granules treated with AAâBEâGA decreased by 52.82 and 48.70%, respectively. Conversely, the macropores increased by 216.68 and 138.18%, respectively. While for maize starch, the percentages of mesopores and macropores hardly changed after three enzyme combinations. Comparing the three enzyme treatments showed that pore volume (0.005 and 0.007 cm3/g) and pore size (36.35 and 26.54 nm) were largest in the AAâBEâGA treated wheat and maize starches, respectively. Compared to the AAâGA and BEâGA, the adsorption capacities for oil, dye and heavy metal ions, wheat starch treated with AAâBEâGA increased by 46.61 and 242.33%, and 44.52 and 134.41%, and 28.83 and 271.72%, respectively. Correspondingly, that of maize starch increased by 29.71 and 133.29%, and 42.92 and 79.93%, and 28.16 and 161.43%, respectively. These results may provide a new and valuable enzyme combination for optimising porous starch granules with higher absorption capacities.
Subject(s)
Adsorption/physiology , Starch/chemistry , Triticum/chemistry , Zea mays/chemistry , 1,4-alpha-Glucan Branching Enzyme/chemistry , 1,4-alpha-Glucan Branching Enzyme/metabolism , Amylases/chemistry , Amylose/chemistry , Glucan 1,4-alpha-Glucosidase/chemistry , Glucan 1,4-alpha-Glucosidase/metabolism , Hydrolysis , Porosity , Temperature , Water/chemistry , alpha-Amylases/chemistry , alpha-Amylases/metabolismABSTRACT
The aim of this study was to carry out the co-immobilization of α-amylase and glucoamylase in crosslinked gelatin porous supports. For this, two methods of co-immobilization were proposed based on the crosslinking with glutaraldehyde (Ggta) or CaCl2 in presence of alginate (Gcal). The supports characterization revealed a porous microstructure with good interaction between its components according to the FTIR analysis and thermal properties. Optimal pH and temperature of the Gcal co-immobilized enzymes were determined at 60 °C and pH 6.0, present an enzymatic activity of 120 µmol·mL·min-1. Moreover, both supports were reused for up to 8 hydrolysis cycles. In addition, co-immobilized enzymes were more efficient than free enzymes in starch saccharification of starch in the long term. These results reveal that the co-immobilization of amylases in gelatinous supports is a promising approach in enzymatic chain reactions.
Subject(s)
Enzymes, Immobilized/chemistry , Gelatin/chemistry , Starch/chemistry , alpha-Amylases/chemistry , Alginates/chemistry , Biocatalysis , Enzyme Stability , Glucan 1,4-alpha-Glucosidase/chemistry , Glutaral/chemistry , Hydrolysis/drug effects , Porosity , TemperatureABSTRACT
1-Deoxynojirimycin (1-DNJ) is the major effective component of mulberry leaves, exhibiting inhibitory activity against α-glucosidase. However, due to the low content of 1-DNJ in mulberry products, its level cannot meet the lowest dose to exhibit its activity. In this study, a combination of dietary 5,6,7-trihydroxy-flavonoid aglycones with 1-DNJ showed synergistic inhibitory activity against maltase of mice α-glucosidase and recombinant C- and N-termini of maltase-glucoamylase (MGAM) and baicalein with 1-DNJ exhibited the strongest synergistic effect. The synergistic effect of the combination was also confirmed by the maltose tolerance test in vivo. Enzyme kinetics, molecular docking, fluorescence spectrum, and circular dichroism spectrometry studies indicated that the major mechanism of the synergism is that baicalein was a positive allosteric inhibitor and bound to the noncompetitive site of MGAM, causing an increase of the binding affinity of 1-DNJ to MGAM. Our results might provide a theoretical basis for the design of dietary supplements containing mulberry products.
Subject(s)
1-Deoxynojirimycin/administration & dosage , Diabetes Mellitus, Type 2/drug therapy , Flavonoids/administration & dosage , Glycoside Hydrolase Inhibitors/administration & dosage , Morus/chemistry , Plant Extracts/administration & dosage , alpha-Glucosidases/metabolism , 1-Deoxynojirimycin/chemistry , Animals , Blood Glucose/metabolism , Diabetes Mellitus, Type 2/enzymology , Diabetes Mellitus, Type 2/metabolism , Drug Synergism , Flavonoids/chemistry , Glucan 1,4-alpha-Glucosidase/antagonists & inhibitors , Glucan 1,4-alpha-Glucosidase/chemistry , Glucan 1,4-alpha-Glucosidase/genetics , Glucan 1,4-alpha-Glucosidase/metabolism , Glycoside Hydrolase Inhibitors/chemistry , Humans , Kinetics , Mice , Mice, Inbred C57BL , Plant Extracts/chemistry , Plant Leaves/chemistry , Postprandial Period/drug effects , alpha-Glucosidases/chemistry , alpha-Glucosidases/geneticsABSTRACT
To explore an effective enzyme combination instead of a common enzyme method, sequential α-amylase and glucoamylase, a method of sequential glycosyltransferase and branching enzyme was chosen to compare the macroscopic features, structure characteristics, porosity characteristics and adsorption quantity of potato, corn, wheat and sweet potato starches. The results indicated that after enzyme treatment, the relative crystallinity of potato, corn, wheat and sweet potato starches increased. Moreover, amylose levels decreased, while pore size and volume, and specific surface area increased after sequential glycosyltransferase and branching enzyme. In terms of pore size, sequential α-amylase and glucoamylase produced abundant mesopores (2-50 nm), whereas sequential glycosyltransferase and branching enzyme developed much more macropores (>50 nm). The adsorption quantities of the starch obtained with sequential glycosyltransferase and branching enzyme were about 2 folds higher than that of the starch obtained with sequential α-amylase and glucoamylase. Therefore, the sequential glycosyltransferase and branching enzyme may be an ideal method to create porous starch as a desirable green adsorbent for industries.
Subject(s)
Glucan 1,4-alpha-Glucosidase/chemistry , Starch/chemistry , alpha-Amylases/chemistry , Adsorption/physiology , Glucan 1,4-alpha-Glucosidase/metabolism , Hydrolysis , Ipomoea batatas/chemistry , Porosity , Solanum tuberosum/chemistry , Triticum/chemistry , Water/chemistry , Zea mays/chemistry , alpha-Amylases/metabolismABSTRACT
OBJECTIVE: To obtain novel glucoamylase from Daqu microbe. RESULTS: A dominant strain known as LZ2 with high activity of hydrolyzing starch was isolated from Luzhou Daqu, a Chinese traditional fermentation starter. The LZ2 was identified as Aspergillus oryzae by 18S rDNA sequence analysis. Glucoamylase from LZ2, named as GA-LZ2, was purified to homogeneity and showed a single band with expected molecular mass of 60 kD. The GA-LZ2 effectively degraded amylose, rice starch and wheat starch. Optimal temperature and pH value of enzyme were 60 °C and pH 4.0 respectively. The GA-LZ2 displayed significant thermal stability and pH stability at moderate temperature and low pH. Intriguingly, the thermostability was enhanced in the presence of starch. In addition, GA-LZ2 exhibited insensitivity to glucose, independence of metal ions and tolerance to organic solvents. The GA-LZ2 retained complete activity in the presence of 100 mM glucose and 5% ethanol and methanol. CONCLUSION: Glucoamylase GA-LZ2 displayed broad substrate specificity, strong stability and tolerance, suggesting that GA-LZ2 carry potential for industrial application in bioethanol production.
Subject(s)
Aspergillus oryzae/classification , Glucan 1,4-alpha-Glucosidase/isolation & purification , RNA, Ribosomal, 18S/genetics , Sequence Analysis, DNA/methods , Amylose/chemistry , Aspergillus oryzae/enzymology , Aspergillus oryzae/genetics , Aspergillus oryzae/isolation & purification , DNA, Fungal/genetics , DNA, Ribosomal/genetics , Enzyme Stability , Fermented Foods , Fungal Proteins/isolation & purification , Fungal Proteins/metabolism , Glucan 1,4-alpha-Glucosidase/chemistry , Glucan 1,4-alpha-Glucosidase/metabolism , Hot Temperature , Hydrogen-Ion Concentration , PhylogenyABSTRACT
The endogenous rutin-degrading enzymes (RDEs) in Tartary buckwheat (TB) considerably limit the development of TB functional foods. In this study, three thermal treatments, including superheated steam (SS), saturated steam (ST), and far-infrared drying (FID), were used to inactivate RDEs in TB. Results showed that SS and ST could efficiently inactivate RDEs, whereas FID could not. The extractable rutin contents in TB were increased by 52.3% and 12.3% by SS and ST, respectively, with 90 s of treatment time. Furthermore, the properties of phenolics and starch were used to evaluate the influence of thermal inactivation on TB. Results showed that the soluble phenolic compounds contents in TB were significantly improved (p < 0.05) by SS. The bound phenolic compounds contents were decreased after SS and ST treatments. The change in antioxidant properties was consistent with that of phenolics and flavonoids. Besides, the starch in SS- and ST-treated TB achenes had higher relative crystallinity, setback, transition temperatures, rapidly digestible starch, and slowly digestible starch contents, but a lower ratio of 1047 cm-1/1022 cm-1, peak viscosity, breakdown, gelatinization enthalpy, and resistant starch contents, than native TB starch. In conclusion, SS was a better method for the inactivation of RDEs than ST.
Subject(s)
Fagopyrum/chemistry , Phenols/chemistry , Rutin/chemistry , Starch/chemistry , Animals , Antioxidants/chemistry , Flavonoids/chemistry , Functional Food , Glucan 1,4-alpha-Glucosidase/chemistry , Pancreas/enzymology , Quercetin/chemistry , Seeds/chemistry , Swine , Temperature , Viscosity , X-Ray Diffraction , alpha-Amylases/chemistryABSTRACT
The handling of conventional enzyme- metal organic framework (MOF) composites is big challenge due to their nano-sized and lightweight structure with low density. Also, conventional MOFs are derived from non-renewable petroleum feedstock which makes them inherent toxic and non-biodegradable. To overcome these difficulties, recently, green, renewable framework material composite, biological metal-organic frameworks (bio-MOFs) have intrigued as a novel class of porous materials. Here, glucoamylase was encapsulated within ZIF-8 in presence of functionalized carboxymethylcellulose (CMC) at mild aqueous conditions. The successful formation of glucoamylase bio-MOF was confirmed by Fourier transform infrared (FT-IR), X-Ray Diffraction (XRD) and scanning electron microscopy (SEM). In thermal stability, glucoamylase bio-MOF exhibited 187 % enhanced thermal stability in the temperature range of 55-75⯰C as compared to native form. Further, glucoamylase bio-MOF was recycled for 5 cycles and compared their activity with traditional glucoamylase MOF. Glucoamylase bio-MOF showed significantly improved recyclability which was attributed by adhesive nature of CMC. Finally, the conformational change occurred in enzyme after immobilization was determined by FT-IR data tools.
Subject(s)
Glucan 1,4-alpha-Glucosidase/metabolism , Metal-Organic Frameworks/metabolism , Aspergillus niger/enzymology , Enzyme Stability , Enzymes, Immobilized/chemistry , Enzymes, Immobilized/metabolism , Glucan 1,4-alpha-Glucosidase/chemistry , Kinetics , Metal-Organic Frameworks/chemistry , Particle Size , Surface Properties , TemperatureABSTRACT
Starch rich foods are almost indispensable in mundane diet of people round the globe. Rapid digestibility of starch culminates into elevated blood glucose level which is an evident factor for many diseases. To curb this rapid digestibility and the elevated glycemic response, resistant starch content in highly nutritious but unexplored popped makhana (Euryale ferox) was increased by amylopullulanase treatment. In the present study, amylopullulanase treated makhana flour (MM) was compared with the native makhana flour (NM) based on physicochemical and functional properties, where enhanced amylose content, resistant starch and crystallinity were recorded to be 12.33 %, 14.88 % and 11.32 % respectively, whereas, readily digestible starch and oil holding capacity decreased by 13.01 % and 3.12â¯g/g respectively. The present study ensures the reduction and sustainable release of glucose during in vitro digestibility analysis. These findings point out the elevated potential of amylopullulanase treated makhana flour for therapeutic food formulation.