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α-amylase is an endonucleoside hydrolase that hydrolyzes the α-1, 4-glycosidic bonds inside polysaccharides, such as starch, to generate oligosaccharides, dextrins, maltotriose, maltose and a small amount of glucose. Due to the importance of α-amylase in food industry, human health monitoring and pharmaceuticals, detection of its activity is widely required in the breeding of α-amylase producing strains, in vitro diagnosis, development of diabetes drugs, and the control of food quality. In recent years, many new α-amylase detection methods have been developed with improved speed and sensitivity. This review summarized recent processes in the development and applications of new α-amylase detection methods. The major principle of these detection methods were introduced, and their advantages and disadvantages were compared to facilitate future development and applications of α-amylase detection methods.
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Humans , alpha-Amylases/chemistry , Polysaccharides , Oligosaccharides , Starch , MaltoseABSTRACT
Objective Taking 41 kinds of Chinese herbal medicines commonly used in Meizhou Hakka as the research object,their inhibitory activities against α-glucosidase and α-amylase were screened and the enzyme inhibition types of the species with the strongest activities were explored.Methods The inhibitory activities of 41 commonly used Hakka herbs in Meizhou against α-glucosidase and α-amylase were evaluated by the p-Nitrophenyl a-D-mannopyranoside(pNPG)method and the 3,5-Dinitrosalicylic acid(DNS)method,using the inhibitory rate of half(IC50)as an index.The inhibitory activity of 95%ethanol extracts of 41 Chinese herbal medicines commonly used in Meizhou Hakka on α-glucosidase and α-amylase were analysed.The enzymatic kinetics method and Lineweaver-Burk curve were used to analyze the inhibitory type of the most active species.Results The results showed that 40 Chinese herbal medicines commonly used in Meizhou Hakka had α-glucosidase inhibitory activity,and 23 medicines had α-amylase inhibitory activity,among which Psychotria asiatica Wall.showed the strongest inhibitory activity with the IC50 values aganist α-glucosidase and α-amylase of 0.17±0.001 mg·mL-1 and 0.09±0.001 mg·mL-1,respectively.The inhibition types were reversible competitive inhibition and reversible non-competitive inhibition,respectively.Conclusion The Psychotria asiatica Wall.Chinese herbal medicines commonly used in Meizhou Hakka has significant inhibitory effect on the activity of glucose metabolism enzymes,which has potential value for further research and development on the prevention and treatment of diabetes mellitus.
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Aspiration is the entry of oropharyngeal or gastric contents into the lower respiratory tract through the glottis, a common and important cause of death in elderly patients due to lung infections.However, a lack of accurate and rapid clinical methods for the diagnosis of aspiration leads to misdiagnosis, missed diagnosis or delayed diagnosis of aspiration, especially aspiration pneumonia.In recent years, with further research into the mechanisms of aspiration syndromes, multiple aspiration biomarkers with potential and clinical translational value have been found, and may help early detection of aspiration and have important and practical significance for elderly health.Therefore, this article reviews aspiration biomarkers such as pepsin, α-amylase, bile acid and other potential biomarkers as well as current relevant research, detection methods, their clinical value and prospects concerning challenges and directions of innovation in future research.
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Objectives: This study aims to investigate the effects of mindful meditation and yoga on reducing burnout and stress in care workers who assist elderly individuals. Knowing how to reduce burnout is important because that of care workers is associated with the quality of client care, worker productivity, and job turnover.Patients and Methods: The participants included 44 care workers who worked for elderly care facilities in rural Fukuoka. They were randomly assigned to one of three intervention groups: control, yoga, or mindfulness. In the yoga intervention group, a certified yoga instructor taught a 60-minute yoga session each week for six weeks. In the mindfulness group, an experienced medical doctor instructed a mindful meditation program for the same length. Participants were asked to complete the Japanese Burnout Scale (JBS), and the research team collected the level of α-amylase in saliva using NIPRO: T-110-N pre- and post-interventions.Results: MANOVA was performed with each intervention (control, yoga, mindfulness) as the independent variable on the three subscales of the JBS (emotional exhaustion, depersonalization, and personal achievement) and a biomarker of stress level (α-amylase). The results indicated a significant main effect of interventions, and a follow-up ANOVA showed a significant effect of interventions on emotional exhaustion and personal achievement.Conclusion: The results indicate that practicing mindful meditation or yoga for 60 minutes once a week for six weeks can reduce care workers’ burnout. This study was notable because the biomarker of stress also improved. It is strongly recommended and encouraged that institutions caring for the elderly population provide mindful meditation or yoga intervention to reduce burnout, which benefits not only care workers but also their clients.
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Objective: An effort currently made to appraise the preliminary phytochemical, pharmacognostic criteria, antioxidant, GCMS and antihyperglycemic investigations of the Thunbergia coccinea leaves. Thunbergia coccinea (T. coccinea) is an ornamental plant considerably practiced by the tribes of forest areas of Assam (INDIA) as an analgesic, antipyretic, anti-inflammatory, antidote, hepatoprotective, antidiabetic and detoxificant substance. Methods: A comprehensive literature survey was conducted to recognize the ethnomedicinal value of T. coccinea, which is currently grown practically in all provinces. The physicochemical constants like moisture content, ash values especially total ash, insoluble acid ash, water-soluble ash and foreign organic matter were determined for the assessment of the drug. Pharmacognostic parameters like fluorescence examination and microscopic characters of the leaf were studied that would serve to verify for contamination. The extract secured by maceration was subjected to the phytochemical inquiry to determine the existence of substances and their antioxidant activity. The antihyperglycemic characteristic of alcoholic extract of the leaf was examined with the inhibition of α-amylase and α-glucosidase enzymes. Gas Chromatography-Mass Spectrometry (GCMS) studies of alcoholic extract of the plant leaf have undertaken to get an insight into the therapeutic properties of the molecules present based on online PASS prediction. Results: Various physicochemical, microscopic parameters studied gave a clear distinguishing and identifying features of T. coccinea leaf. Phytochemical screening gave an insight into the secondary metabolites existing in the plant leaf through picturizing its therapeutic properties against various ailments. Both extracts of T. coccinea leaf showed enhanced antioxidant activities. Nevertheless, the alcoholic leaf extract has shown significant antioxidant activity with an IC50 of 171.38±2.51 μg/ml and AQTC an IC50 value of 206.29±4.5 μg/ml respectively by DPPH method. Further, ACTC showed a better-reducing potential with an IC50 value of 105.74±0.61 μg/ml in comparison with AQTC IC50 value of 203.702±0.97 μg/ml by FRP method. The inhibition potentiality of α-amylase and α-glucosidase was found to be 71.66 % and 83.74 %, respectively at 500 µg/ml that rationally an adequate remedy in the treatment of type-2 diabetes. GCMS studies of the alcoholic extract unveiled the presence of different molecules like Glycerol, tris (trimethylsilyl) ether, 3,7,11,15-Tetramethyl-2-hexadecen-1-ol, Undecanoic acid, Ethyl ester, Phytol in comparison with NIST library, thereby giving its predicted therapeutic properties like sugar phosphatase inhibitor, antifungal, phobic disorders treatment, antiviral and so on. Conclusion: The selected plant had many proven therapeutic traits and, possibly, successively united on to the sort of potential therapeutic plants. Besides, isolation and discoveries will lead to the detection of certain novel compounds, which will be of potential medicinal value.
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The study aimed to investigate the phytochemical profiles, in vitro antioxidant activity, and in silico molecular dockingantidiabetic activity of the aqueous root extracts of Ruellia tuberosa L. The phytochemical qualitative tests revealedthe positive detections of tannins, flavonoids, ascorbic acid, and phenolic compounds. Using Liquid chromatographyhigh-resolution mass spectrometry (LC-HRMS) analysis, 12 compounds were tentatively identified in the extracts.The major compounds were tentatively identified as betaine, daidzein, hispidulin, α-linoleic acid, and 4-coumaric acid.The aqueous root extracts have high antioxidant activity with the IC50 value of 15.2 mg/ml against DPPH free radicals.The major putatively identified compounds were docked to human pancreatic α-amylase protein, to investigate theirinhibitory activities to this enzyme. The interaction between betaine, daidzein, and hispidulin in docking with humanpancreatic a-amylase showed different binding sites to the protein. In addition, the types of bonds involved weremostly hydrogen and hydrophobic bonds which show the interactions between three ligands and α-amylase. Energygenerated from docking between betaine, daidzein, and hispidulin with α-amylase was −137.6, −245.8, and −236.7cal/mol, respectively. This study concludes that the aqueous root extracts of R. tuberosa L. have prospective as aninhibitor for a-amylase protein and to be used as antidiabetic agent. Further, in vitro and in vivo studies are needed toconfirm this work.
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Objective: To investigate the in vivo and in vitro antidiabetic potential of Chrysophyllum albidum. Methods: The effects of oral treatment with hydro-ethanolic extract (125, 250 and 500 mg/kg) of the stem bark of Chrysophyllum albidum and glibenclamide for 21 d on glucose level, serum enzyme markers for liver function, lipid profile, total protein, serum urea, serum creatinine, and body weight were evaluated in experimental diabetic rats administered with 45 mg/kg of streptozotocin. In vitro assays including glucose uptake in C2C12 cells and 3T3-L1 adipose tissues, α-glucosidase and α-amylase inhibition were employed to evaluate the possible mechanism of hypoglycemic action of the extract. DPPH and nitric oxide radical antioxidant activity of the extract was also measured. Results: The increased levels of blood glucose, triglycerides, low-density lipoprotein, total cholesterol, serum aspartate, and alanine transaminases, creatinine, and urea in the diabetic animals were reduced significantly (P<0.01) after treatment with Chrysophyllum albidum extract. The decreased total protein and high-density lipoprotein concentrations were normalized after treatment. In addition, the extract significantly (P<0.01) increased the transport of glucose in 3T3-L1 cells and C2C12 myotubes and exhibited considerable potential to inhibit α-amylase and α-glucosidase. It also demonstrated potent antioxidant action by scavenging considerably DPPH and nitric oxide radicals. Conclusions: Chrysophyllum albidum stem bark extract exhibits considerable antidiabetic effect by stimulating glucose uptake and utilization in C2C12 myotubes and 3T3-L1 adipocytes as well as inhibiting the activities of α-amylase and α-glucosidase.
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Objective: To investigate the in vivo and in vitro antidiabetic potential of Chrysophyllum albidum. Methods: The effects of oral treatment with hydro-ethanolic extract (125, 250 and 500 mg/kg) of the stem bark of Chrysophyllum albidum and glibenclamide for 21 d on glucose level, serum enzyme markers for liver function, lipid profile, total protein, serum urea, serum creatinine, and body weight were evaluated in experimental diabetic rats administered with 45 mg/kg of streptozotocin. In vitro assays including glucose uptake in C2C12 cells and 3T3-L1 adipose tissues, α-glucosidase and α-amylase inhibition were employed to evaluate the possible mechanism of hypoglycemic action of the extract. DPPH and nitric oxide radical antioxidant activity of the extract was also measured. Results: The increased levels of blood glucose, triglycerides, low-density lipoprotein, total cholesterol, serum aspartate, and alanine transaminases, creatinine, and urea in the diabetic animals were reduced significantly (P<0.01) after treatment with Chrysophyllum albidum extract. The decreased total protein and high-density lipoprotein concentrations were normalized after treatment. In addition, the extract significantly (P<0.01) increased the transport of glucose in 3T3-L1 cells and C2C12 myotubes and exhibited considerable potential to inhibit α-amylase and α-glucosidase. It also demonstrated potent antioxidant action by scavenging considerably DPPH and nitric oxide radicals. Conclusions: Chrysophyllum albidum stem bark extract exhibits considerable antidiabetic effect by stimulating glucose uptake and utilization in C2C12 myotubes and 3T3-L1 adipocytes as well as inhibiting the activities of α-amylase and α-glucosidase.
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The study was intended to investigate anti-diabetic efficacy of Aerva lanata by determining its α-amylase inhibition activity and in vitro uptake of glucose in adipose tissue and psoas muscle isolated from male Sprague Dawley (SD) rats. Aerva lanata is reported to have many traditional and Ayurvedic uses. Male SD rats (n=3) of 150 g were sacrificed and 250 mg of respective tissues were isolated for the study. Aerva lanata ethanolic extract (ALE) (5-20 mg/mL) showed 13.30 to 54.08% α-amylase inhibition activity. Glucose uptake studies in in vitro conditions were carried out in both adipose tissue and psoas muscle in different sets - tissue alone, tissue along with (Aerva lanata extract: 50µg, 100µg, 150µg, insulin: 25 mU/L, insulin: 50 mU/L and Aerva lanata extract: 50µg + insulin: 25 mU/L, Aerva lanata extract: 100µg + insulin: 25 mU/L, Aerva lanata extract: 150µg + insulin: 25 mU/L, Aerva lanata extract: 50µg + insulin: 50 mU/L, Aerva lanata extract: 100µg + insulin: 50 mU/L, Aerva lanata extract: 150µg + insulin: 50 mU/L). The rate of glucose uptake by insulin action in these tissues was stabilized by ethanolic extract of Aerva lanata and this shows synergetic activity of insulin and Aerva lanata.
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In the present study an attempt has been made to evaluate the phytochemical, antimicrobial, antioxidant and α-amylase inhibitory activity of Coccinia indica(W. and A) leaf extracts using four solvents and compare it with the callus extracts. Callus was initiated from the leaf explants of C.indicawith 90% efficiency using MS medium supplemented with BAP (1 mg/l) + NAA (0.2 mg/l). Successive extraction method of C.indicawas found to be an efficient method of extraction and methanol was observed to be the best suited solvent for the extraction of phytochemicals and macromolecules that were responsible for antimicrobial, antioxidant and α-amylase inhibition. GC-MS analysis of C.indicahas confirmed the presence of bioactive compounds (Example: 9-Octadecanoic acid, 2-octadecycloxy ethyl ester (100%) in successive methanolic callus extract) in all the extracts where the FTIR analysis has confirmed the presence of various important functional groups of the identified bioactive compounds. Successive methanol extract of callus of C.indicawas found to be the potent antimicrobial agent with drug efflux pump inhibitor property against 5 bacterial strains, Klebsiella pneumoniae (ATCC700603), Escherichia coli (ATCC25922), Staphylococcus aureus (ATCC 25923), Proteus mirabilis (ATCC 25933)and Pseudomonas aeruginosa (clinical isolate) and 3 fungal strains, Candida albicans (IFM 40009), Candida tropicalis (IFM 55058)andCandida krusei (IFM 46521).Successive methanol extract of callus of C.indicawas found to be an efficient antioxidant agent and an efficient α-amylase inhibitor, which proves it to be a potent anti-diabetic agent with IC50 concentration to be 82.5μg/ml. This study is one of the strong evidence for this plant to be used by the traditional practitioners as a phytopharmaceutical agent
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Aim: The present study was carried out to enhance the production of α-amylase by pelleted Aspergillus tamarii through optimization of various media compositions and cultivation conditions using shake flask and bioreactor experiments. Methodology: Shake flask experiments were conducted to study the effect of pH, temperature and starch concentration using Response Surface Methodology (RSM) and other parameters, namely, nitrogen source, inoculum size and incubation days using single variable optimization technique for the pelleted growth of microorganism and amylase production. Scale up study was carried out for the assessment of results obtained from shake flask experiments using a laboratory scale bioreactor. In the bioreactor study, parameters, namely, pH control, agitation and aeration were considered. Results: Maximum amylase production using pelleted Aspergillus tamarii was achieved at initial pH 6.7, temperature 30.5 °C, 0.5% w/v starch, 0.1% w/v urea, 1.5% v/v inoculum size and 4 days of fermentation in the shake flask experiments. Filamentous growth was observed when the concentration of starch used was above 2%. The specific enzyme activity increased to 2.77 fold after partial purification. When enzyme was used for desizing cotton fabric, it produced 90% efficiency. The scale-up experiments revealed initial pH 6.7, agitation 300 rpm and aeration 1 vvm as the conditions suitable for pelleted growth, as well as to achieve maximum amylase production. Interpretation: The results indicate pelleted growth of Aspergillus tamarii and in turn achievement of maximum amylase activity depends on media composition and fermentation conditions used at the time of enzyme production. Efficient desizing of cotton fabric by amylase showed its effectiveness towards hydrolysis of starch and converting it to soluble products for easy removal.
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Diabetes mellitus is a clinical disease categorized by hyperglycemia. Reduction of gastrointestinal glucose absorptionthrough the inhibition of carbohydrate digesting enzymes is one of in vitro anti-diabetic therapeutic approach. Thisinvestigation aimed to estimate the in vitro anti-diabetic and anti-obesity activities for ethyl acetate and methanolextracts of Commiphora myrrha oleo-gum as well as the identification of the bioactive compounds. Commiphoramyrrha was extracted with methanol and ethyl acetate. The two extracts were used to evaluate their α-glucosidase,α-amylase, and pancreatic lipase inhibitory activities. Identification of the bioactive compounds of ethyl acetate wasanalyzed by GC-MS (gas chromatography-mass spectrometry). The results showed that the ethyl acetate extract hada stronger inhibition activity on α-amylase (IC50 = 54.60 µg/ml) and α-glucosidase (IC50 = 58.7 µg/ml) than methanolextract on α-amylase (IC50 = 124.01 µg/ml) and α-glucosidase (IC50 = 191.2 µg/ml). Also, ethyl acetate extract hada promising inhibitory effect on pancreatic lipase (IC50 = 107.8 µg/ml) than methanol extract (IC50 = 498.1 µg/ml).GC-MS analysis of ethyl acetate extract identified 31 compounds. Among them nobiletin (50.26%), metaproterenol(orciprenaline) (14.99%), morantel (8.86%), and tricetin (3.38%) were the main compounds. These findings provedthat C. myrrha has anti-diabetic and anti-obesity inhibition activity may be due to the bioactive compounds withinteresting medicinal properties.
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The purpose of this study is to show the phytochemical composition and in vitro antidiabetic potential in the leaves of Ceriops tagal, Bruguiera cylindrica, and Salvadora persica mangrove plants. The phytochemical composition was studied by qualitative analysis. To determine in vitro antidiabetic activity leaves were subjected to solvent extraction by the Soxhlet method using methanol, ethanol, ethyl acetate, and pet ether and α-amylase, α-glucosidase inhibition assays were performed. The findings indicates that alkaloid, steroid, flavonoid, terpenoid, glycosides, tannin, saponin, phenol, quinones and coumarin principles are present in the leaves of selected mangrove species. Among the selected mangrove species C. tagal leaves recorded the highest antidiabetic activity for both the assay followed by B. cylidrica and S. persica. Overall C. tagal was found highly potent in the antidiabetic activity.
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OBJECTIVE： To compare inhibitory effects of ethanol extract of different medicinal parts （root， stem， leaf， seed， flower and flesh） from Syzygium jambos on the activities of α-glycosidase and α-amylase. METHODS： Using half-inhibitory concentration value （IC50） as evaluation index， acarbose as positive control， inhibitory effects of ethanol extract of different medicinal parts from S. jambos on the activities of α-glycosidase （from yeast and small instestine in mice） and α-amylase were evaluated with in vitro inhibition model. The enzymatic dynamics and Lineweaver-Burk methods were used to analyze the inhibitory type of the best medicinal part on the activities of α-glycosidase and α-amylase. RESULTS： In the yeast α-glucosidase inhibitory activity test， the order of inhibitory activity was S. jambos seed＞S. jambos stem＞S. jambos leaf＞S. jambos root＞S. jambos flower＞S. jambos flesh＞acarbose. In the mice intestine α-glucosidase inhibitory activity test， the order of inhibitory activity was S. jambos seed＞S. jambos stem＞S. jambos root＞S. jambos leaf＞S. jambos flower＞S. jambos flesh＞acarbose. In the α-amylase inhibitory activity test， the order of inhibitory activity was acarbose＞S. jambos seed＞S. jambos stem＞S. jambos root＞S. jambos leaf＞S. jambos flesh＞S. jambos flower. Ethanol extract of S. jambos seed had the stronger inhibition activity against α-glucosidase from yeast，α-glucosidase from small intestine in mice and α-amylase than other medicinal parts [IC50 were（6.64±0.24）， （32.77±2.46） and （41.18±1.63） μg/mL]. Ethanol extract of S. jambos seed had the stronger inhibition activity against α-glucosidase than acarbose [IC50 to α-glucosidase from yeast and α-glucosidase from small intestine in mice were （2 833.33±5.48）， （1 304.21±6.45） μg/mL] （P＜0.05）. The inhibitory effect of ethanol extract from S. jambos on the activity of α-amylase was less than that of acarbose [IC50 was （27.27±1.24） μg/mL] （P＜0.05）. Enzymatic dynamics showed that the inhibitory type of ethanol extract from S. jambos seed on α-glucosidase and α-amylase were both reversible competitive inhibition. CONCLUSIONS： Among different parts of S. jambos such as root， stem， leaf， seed， flower and flesh， S. jambos seed shows the strongest inhibitory effects on the activities of α-glucosidase and α-amylase， which has the value of being developed for the treatment of diabetes or health food.
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The non-starch polysaccharides,mainly composed of glucomannans,are the major bioactive compounds in Dendrobium catenatum. In order to evaluate the quality of the medicinal materials and guide the production and processing,a quantification method of non-starch polysaccharides was established by stems of D. catenatum C15 strain collected from the pear epiphytic cultivation. The non-starch polysaccharides were obtained by " water extraction,α-amylase pretreatment,and alcohol precipitation once" method. The contents of starches,non-starch polysaccharides and monosaccharides were analyzed. In addition,the system suitability was tested. Compared with method of the Chinese Pharmacopoeia( 2015 edition),the contents of total polysaccharides,glucose,and mannose were decreased by 20. 9%,58. 8% and 1. 6% respectively. The method effectively digested starch and retained non-starch polysaccharides,and the analysis result was accurate and repeatable. Therefore,it is suitable for the content measurement of non-starch polysaccharides of D. catenatum. Furthermore,it could be an alternative method for quality control of D. catenatum and a reference in the determination of non-starch polysaccharides in other starch-containing medicinal materials.
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Dendrobium , Chemistry , Monosaccharides , Phytochemicals , Polysaccharides , StarchABSTRACT
@#Aim:The study aimed at isolation, screening, optimization and partial purification of α-amylase and evaluating its desizing efficiency in textile industry. Methodology and results:The AF01 showed the highest α-amylase activity of 128 KU. This isolate was identified asAspergillus luchuensisstrain bs1 using 18S rRNA gene sequencing. The process parameters were screened by employing Plackett-Burman Design (PBD) with seven variables and followed by Box-Behnken Design with three positively influencing factors. The investigation revealed that the maximum α-amylase production (192KU) at medium pH 5.6, starch 3% (w/v) and sodium nitrate 0.5% (w/v). The partial purification of α-amylase was done by acetone precipitation and it resulted in 6.1 fold purification. Partially purified α-amylase recorded optimum activity at pH 5.5, 60 min of contact time, temperature stability at 60°C and 93%specificity to potato starch. The desized cotton fabric showed 9.5% weight loss, 5 sec of absorbency time and 8 rating in Tegewa analysis.Conclusion, significance and impact of study: The study proposes a novel indigenous fungal strain having ability to produce alpha amylase and an enzyme preparation for desizing sized cotton fabric in minimal concentration.
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<p><b>OBJECTIVE</b>The current study was designed to evaluate the various antioxidant potentials and inhibitory effects of phenolic-rich leaf extracts of Bridelia ferruginea (BF) on the in vitro activities of some key enzymes involved in the metabolism of carbohydrates.</p><p><b>METHODS</b>In this study, BF leaf free and bound phenolic-rich extracts were used. We quantified total phenolic and flavonoid contents, and evaluated several antioxidant activities using assays for ferric reducing antioxidant power, total antioxidant activity (phosphomolybdenum reducing ability), 1,1-diphenyl-2-picrylhydrazyl and thiobarbituric acid reactive species. Also, extracts were tested for their ability to inhibit α-amylase and α-glucosidase activity.</p><p><b>RESULTS</b>The total phenolic and total flavonoid contents in the free phenolic extract of BF were significantly greater than in the bound phenolic extract. Also, all the antioxidant activities considered were significantly greater in the free phenolic extract than in the bound phenolic extract. In the same vein, the free phenolic-rich extract had a significantly higher percentage inhibition against α-glucosidase activity (IC = 28.5 µg/mL) than the bound phenolic extract (IC = 340.0 µg/mL). On the contrary, the free phenolic extract (IC = 210.0 µg/mL) had significantly lower inhibition against α-amylase than the bound phenolic-rich extract (IC = 190.0 µg/mL).</p><p><b>CONCLUSION</b>The phenolic-rich extracts of BF leaves showed antioxidant potentials and inhibited two key carbohydrate-metabolizing enzymes in vitro.</p>
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Animals , Humans , Rats , Antioxidants , Chemistry , Pharmacology , Diabetes Mellitus, Type 2 , Metabolism , Enzyme Inhibitors , Chemistry , Pharmacology , Glycoside Hydrolase Inhibitors , Chemistry , Pharmacology , Iron , Magnoliopsida , Chemistry , Oxidative Stress , Pancreas , Metabolism , Phenols , Chemistry , Pharmacology , Plant Extracts , Chemistry , Pharmacology , Swine , alpha-Amylases , Chemistry , alpha-Glucosidases , ChemistryABSTRACT
Fungal α-amylases are widely used in the production of maltose syrup, while additional production costs may be required in the syrup production process due to the loss of enzyme activity, because of the poor thermostability exhibited in this type of enzyme. After deeply studying the importance of thermostability of fungal α-amylases applied in industrial production, with attempt to improve the thermostability of Rhizopus oryzae α-amylase (ROAmy), single-point mutations and combined mutations that based on analysis of B-factor values and molecular dynamics simulations were carried out for amino acid residues G128, K269 and G393 of ROAmy by overlapping PCR. The results showed that all the 7 mutants obtained presented better thermostability than the wild-type enzyme, and the best mutant was G128L/K269L/G393P which showed a 5.63-fold increase in half-life at 55 ℃ compared with the wild-type enzyme. Meanwhile, its optimum temperature increased from 50 ℃ to 65 ℃, the maximum reaction rate (Vmax) and catalytic efficiency (kcat/Km) increased by 65.38% and 99.86%. By comparing and analyzing the protein structure and function between the mutants and the wild-type enzyme, it was found that the increase of the number of hydrogen bonds or the introduction of proline in special position may be the main reasons for the improved thermostability that found in the mutants.
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We are facing increasing stress and challenges because of the fierce competition and fast pace of daily work and life.In other words,we are exposed to more frequent and intense social stress.Continual and intense stress is known to be detrimental to human well-being.Stress has been regarded as a major contributing factor of human diseases.There-fore,it′s necessary to review the recent research progress in stress biomarkers that are of different types,such as cortisol,α-amylase,catecholamine,heat shock protein and cytokines.In this review,we will focus on the most well reported stress biomarkers,including cortisol and α-amylase.We hope that this review will enable researchers and practitioners to gain in-sights into stress biomarkers,which will lead to improved healthcare decisions regarding prevention,treatment and rehabili-tation of stress-related diseases.
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Objective To select the calibrator for the conventional measurement system of serum a-Amylase (Amy).Methods The Amy levels of forty frozen serum samples were detected by the IFCC reference method (reference system),the conventional system A which used the Bioassay routine reagent and Randox calibrator,and was calibrated by the Roche PNPG7 method,and the conventional system B which used the Bioassay routine reagent and Randox calibrator,and was calibrated by the Rondox liquid stable PNPG7 method,respectively,and the acceptability of the two conventional systems was evaluated.Results The regression equations of the measurement values between the IFCC reference method and the conventional systems A and B were Y =0.964X +0.376 and Y =1.095X + 3.131,respectively.Among them,X and Y represented the results of the IFCC reference method and the conventional system,respectively.Compared with the IFCC reference method,the results of the conventional system A was reliable.Condusion With the guidance of the IFCC reference method,the domestic biochemical reagents matched with the suitable calibrators may provide the acceptable results.