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FEBS Letters Jun 1992The recent state of the knowledge of properties and structure of alpha-amylases is reviewed with the aim of elucidation the basis for their stabilization. Three... (Review)
Review
The recent state of the knowledge of properties and structure of alpha-amylases is reviewed with the aim of elucidation the basis for their stabilization. Three principal ways for obtaining stable alpha-amylases (isolation of enzymes from extremophiles, production of extremophilic enzymes in mesophiles, and modification of mesophilic enzymes) are discussed separately. Detailed experimental examples are given for modification approaches.
Topics: Enzyme Stability; alpha-Amylases
PubMed: 1618293
DOI: 10.1016/0014-5793(92)80575-2 -
BioMed Research International 2021The leaves of have been used in the management of diabetes mellitus in Ethiopian folk medicine. Thus, this study is aimed at investigating the -amylase and -glucosidase...
BACKGROUND
The leaves of have been used in the management of diabetes mellitus in Ethiopian folk medicine. Thus, this study is aimed at investigating the -amylase and -glucosidase inhibitory and antioxidant activities of the crude extract and solvent fractions of leaves.
METHODS
The -amylase and -glucosidase inhibitory and antioxidant activities of the plant extract were assessed using 3,5-dinitrosalicylic acid (DNSA), p-nitro-phenyl-a-D glucopyranoside (p-NPG), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays, respectively. Each value of percent inhibition of -amylase, -glucosidase, and DPPH scavenging effect was presented as means ± SEM ( = 3).
RESULTS
The -amylase inhibitory activity of the crude extract and solvent fractions was found to be concentration-dependent. The strongest activity was exhibited by the crude extract at the highest concentration with a percentage inhibition of 74.52% (IC, 14.52 g/ml) followed by water fraction 68.24% (IC, 16.31 g/ml), ethyl acetate fraction 61.57% (IC, 18.73 g/ml), and chloroform fraction 56.87% (IC, 21.57 g/ml) of leaves. In the -glucosidase inhibition assay, the maximum activity was exhibited by the fraction 62.54% (IC, 11.67 g/ml) followed by ethyl acetate fraction 54.97% (IC, 15.89 g/ml), crude extract 46.79% (IC, >16.5 g/ml), and chloroform fraction 36.44% (IC, >16.5 g/ml). In the antioxidant assay, the crude extract exhibited the highest antioxidant activity 86.36% (IC, 10.25 g/ml) followed by water fraction 78.59% (IC, 13.86 g/ml), ethyl acetate fraction 71.58% (IC, 16.34 g/ml), and chloroform fraction 63.65% (IC, 18.83 g/ml).
CONCLUSION
This study has revealed that leaves possess noticeable -amylase and -glucosidase inhibitory and antioxidant activities.
Topics: Antioxidants; Glycoside Hydrolase Inhibitors; Phytochemicals; Plant Extracts; Plant Leaves; Rosaceae; Solvents; alpha-Amylases; alpha-Glucosidases
PubMed: 33987444
DOI: 10.1155/2021/6652777 -
Journal of Medicine and Life Apr 2022Islamic praying (Namaz) can be considered a mental, spiritual, and physical practice. The study aimed to investigate the early effect of Namaz on stress-related hormones...
Islamic praying (Namaz) can be considered a mental, spiritual, and physical practice. The study aimed to investigate the early effect of Namaz on stress-related hormones and the expression of stress-induced genes such as IL6 and BDNF. Eighty-three healthy women and men who continually practice Namaz participated in the study. The saliva samples were taken before and after Namaz to measure cortisol and alpha-amylase hormone levels. Also, to evaluate the expression of BDNF and IL6 genes, 11 specimens were selected randomly. Based on baseline sampling, the participants were classified into three groups: cortisol levels lower than 5, between 5-15, and upper than 15 ng/ml. The results indicated that cortisol significantly increased and decreased in the first and third groups after Namaz, respectively. In addition, the increase of alpha-amylase also occurred in subjects with a low baseline level of its concentration. Regarding genetic expression examination, there was a significant decrease in BDNF gene expression after the Namaz. In addition, the change of cortisol and alpha-amylase hormones after Namaz related to the baseline level changed to approach the optimal range after Namaz. These findings were reported for the first time and need more studies.
Topics: Brain-Derived Neurotrophic Factor; Female; Humans; Hydrocortisone; Interleukin-6; Male; Saliva; Stress, Psychological; alpha-Amylases
PubMed: 35646186
DOI: 10.25122/jml-2021-0167 -
International Archives of Allergy and... 2013
Topics: Allergens; Animals; Cockroaches; Cross Reactions; Environmental Exposure; High-Throughput Screening Assays; Humans; Hypersensitivity; Immunoglobulin E; Insect Proteins; Proteomics; alpha-Amylases
PubMed: 23689492
DOI: 10.1159/000350207 -
BioMed Research International 2020Postprandial hyperglycemia and oxidative stress are important factors that worsen the health condition of patients with type 2 diabetes. We recently showed that extracts...
Postprandial hyperglycemia and oxidative stress are important factors that worsen the health condition of patients with type 2 diabetes. We recently showed that extracts from mitigate hyperglycemia in dexamethasone- and high diet/streptozotocin-induced diabetes. Herein, we evaluated the postprandial regulatory properties and the antioxidant effects of the aqueous (AE) and methanol (ME) extracts from the stem bark of . The phytochemical analysis of AE and ME was performed using the LC-MS technique and the total phenolic and flavonoid assays. Both extracts were tested for their ability to inhibit superoxide anion (O ), hydrogen peroxide (HO), protein oxidation, alpha-amylase, and alpha-glucosidase activities. The mode of enzyme inhibition was also determined in a kinetic study. AE and ME were both rich in phenolic and flavonoid compounds. ME was 2.13 and 1.91 times more concentrated than AE in phenolic and flavonoid compounds, respectively. LC-MS allowed the identification of 5 compounds in both extracts. ME and AE inhibited O with IC of 51.81 and 34.26 g/ml, respectively. On HO, they exhibited IC of 44.84 and 1.78 g/ml, respectively. Finally, they exhibited IC of 120.60 and 140.40 g/ml, respectively, in the inhibition of protein oxidation induced by HO, while showing IC of 39.26 and 97.95 g/ml on the protein oxidation induced by AAPH. ME and AE inhibited alpha-amylase with IC of 6.15 and 54.52 g/ml, respectively. These extracts also inhibited alpha-glucosidase, demonstrating IC of 76.61 and 86.49 g/ml. AE exhibited a mixed noncompetitive inhibition on both enzymes, whereas ME exhibited a competitive inhibition on -amylase and a pure noncompetitive inhibition on -glucosidase. These results demonstrate that ME and AE scavenge reactive oxygen species and prevent their effects on biomolecules. Besides, ME and AE inhibit carbohydrate digestive enzymes. These properties may contribute to reduce postprandial hyperglycemia and regulate glycemia in diabetic patients.
Topics: Animals; Antioxidants; Ceiba; Glycoside Hydrolase Inhibitors; Humans; Plant Bark; Plant Extracts; alpha-Amylases; alpha-Glucosidases
PubMed: 32382543
DOI: 10.1155/2020/3063674 -
BMC Genomics Apr 2023Starch hydrolysates are energy sources for plant growth and development, regulate osmotic pressure and transmit signals in response to both biological and abiotic...
BACKGROUND
Starch hydrolysates are energy sources for plant growth and development, regulate osmotic pressure and transmit signals in response to both biological and abiotic stresses. The α-amylase (AMY) and the β-amylase (BAM) are important enzymes that catalyze the hydrolysis of plant starch. Cassava (Manihot esculenta Crantz) is treated as one of the most drought-tolerant crops. However, the mechanisms of how AMY and BAM respond to drought in cassava are still unknown.
RESULTS
Six MeAMY genes and ten MeBAM genes were identified and characterized in the cassava genome. Both MeAMY and MeBAM gene families contain four genes with alternative splicing. Tandem and fragment replications play important roles in the amplification of MeAMY and MeBAM genes. Both MeBAM5 and MeBAM10 have a BZR1/BES1 domain at the N-terminus, which may have transcription factor functions. The promoter regions of MeAMY and MeBAM genes contain a large number of cis-acting elements related to abiotic stress. MeAMY1, MeAMY2, MeAMY5, and MeBAM3 are proven as critical genes in response to drought stress according to their expression patterns under drought. The starch content, soluble sugar content, and amylase activity were significantly altered in cassava under different levels of drought stress.
CONCLUSIONS
These results provide fundamental knowledge for not only further exploring the starch metabolism functions of cassava under drought stress but also offering new perspectives for understanding the mechanism of how cassava survives and develops under drought.
Topics: Drought Resistance; Manihot; beta-Amylase; alpha-Amylases; Droughts; Gene Expression Regulation, Plant; Stress, Physiological; Plant Proteins
PubMed: 37024797
DOI: 10.1186/s12864-023-09282-9 -
BMC Biotechnology May 2021Amylases produced by fungi during solid-state fermentation are the most widely used commercial enzymes to meet the ever-increasing demands of the global enzyme market....
BACKGROUND
Amylases produced by fungi during solid-state fermentation are the most widely used commercial enzymes to meet the ever-increasing demands of the global enzyme market. The use of low-cost substrates to curtail the production cost and reuse solid wastes are seen as viable options for the commercial production of many enzymes. Applications of α-amylases in food, feed, and industrial sectors have increased over the years. Additionally, the demand for processed and ready-to-eat food has increased because of the rapid growth of food-processing industries in developing economies. These factors significantly contribute to the global enzyme market. It is estimated that by the end of 2024, the global α-amylase market would reach USD 320.1 million (Grand View Research Inc., 2016). We produced α-amylase using Aspergillus oryzae and low-cost substrates obtained from edible oil cake, such as groundnut oil cake (GOC), coconut oil cake (COC), sesame oil cake (SOC) by solid-state fermentation. We cultivated the fungus using these nutrient-rich substrates to produce the enzyme. The enzyme was extracted, partially purified, and tested for pH and temperature stability. The effect of pH, incubation period and temperature on α-amylase production using A. oryzae was optimized. Box-Behnken design (BBD) of response surface methodology (RSM) was used to optimize and determine the effects of all process parameters on α-amylase production. The overall cost economics of α-amylase production using a pilot-scale fermenter was also studied.
RESULTS
The substrate optimization for α-amylase production by the Box-Behnken design of RSM showed GOC as the most suitable substrate for A. oryzae, as evident from its maximum α-amylase production of 9868.12 U/gds. Further optimization of process parameters showed that the initial moisture content of 64%, pH of 4.5, incubation period of 108 h, and temperature of 32.5 °C are optimum conditions for α-amylase production. The production increased by 11.4% (10,994.74 U/gds) by up-scaling and using optimized conditions in a pilot-scale fermenter. The partially purified α-amylase exhibited maximum stability at a pH of 6.0 and a temperature of 55 °C. The overall cost economic studies showed that the partially purified α-amylase could be produced at the rate of Rs. 622/L.
CONCLUSIONS
The process parameters for enhanced α-amylase secretion were analyzed using 3D contour plots by RSM, which showed that contour lines were more oriented toward incubation temperature and pH, having a significant effect (p < 0.05) on the α-amylase activity. The optimized parameters were subsequently employed in a 600 L-pilot-scale fermenter for the α-amylase production. The substrates were rich in nutrients, and supplementation of nutrients was not required. Thus, we have suggested an economically viable process of α-amylase production using a pilot-scale fermenter.
Topics: Aspergillus oryzae; Bioreactors; Culture Media; Enzyme Stability; Fermentation; Fungal Proteins; Hydrogen-Ion Concentration; Industrial Microbiology; Plant Oils; Temperature; Waste Products; alpha-Amylases
PubMed: 33947396
DOI: 10.1186/s12896-021-00686-7 -
BMC Biochemistry Jun 2018Previous studies have demonstrated that members of Trichoderma are able to generate appreciable amount of extracellular amylase and glucoamylase on soluble potato...
BACKGROUND
Previous studies have demonstrated that members of Trichoderma are able to generate appreciable amount of extracellular amylase and glucoamylase on soluble potato starch. In this study the α-amylase was purified and characterized from Trichoderma pseudokoningii grown on orange peel under solid state fermentation (SSF).
RESULTS
Five α-amylases A1-A5 from Trichodrma pseudokoningii were separated on DEAE-Sepharose column. The homogeneity of α-amylase A4 was detected after chromatography on Sephacryl S-200. α-Amylase A4 had molecular weight of 30 kDa by Sephacryl S-200 and SDS-PAGE. The enzyme had a broad pH optimum ranged from 4.5 to 8.5. The optimum temperature of A4 was 50 °C with high retention of its activity from 30 to 80 °C. The thermal stability of A4 was detected up to 50 °C and the enzyme was highly stable till 80 °C after 1 h incubation. All substrate analogues tested had amylase activity toward A4 ranged from 12 to 100% of its initial activity. The Km and Vmax values of A4 were 4 mg starch/ml and 0.74 μmol reducing sugar, respectively. The most of metals tested caused moderate inhibitory effect, except of Ca and Mg enhanced the activity. Hg and Cd strongly inhibited the activity of A4. EDTA as metal chelator caused strong inhibitory effect.
CONCLUSIONS
The properties of the purified α-amylase A4 from T. pseudokoningii meet the prerequisites needed for several applications.
Topics: Chromatography, Ion Exchange; Citrus sinensis; Electrophoresis, Polyacrylamide Gel; Enzyme Stability; Fermentation; Fungal Proteins; Hot Temperature; Hydrogen-Ion Concentration; Isoenzymes; Molecular Weight; Substrate Specificity; Trichoderma; alpha-Amylases
PubMed: 29902965
DOI: 10.1186/s12858-018-0094-8 -
Journal of Nutritional Science and... Apr 2006The inhibitory activity of six groups of flavonoids against yeast and rat small intestinal alpha-glucosidases and porcine pancreatic alpha-amylase was compared, and...
The inhibitory activity of six groups of flavonoids against yeast and rat small intestinal alpha-glucosidases and porcine pancreatic alpha-amylase was compared, and chemical structures of flavonoids responsible for the inhibitory activity were evaluated. Yeast alpha-glucosidase was potently inhibited by the anthocyanidin, isoflavone and flavonol groups with the IC50 values less than 15 microM. The following structures enhanced the inhibitory activity: the unsaturated C ring, 3-OH, 4-CO, the linkage of the B ring at the 3 position, and the hydroxyl substitution on the B ring. Rat small intestinal alpha-glucosidase was weakly inhibited by many flavonoids, and slightly by the anthocyanidin and isoflavone groups. 3-OH and the hydroxyl substitution on the B ring increased the inhibitory activity. In porcine pancreatic alpha-amylase, luteolin, myricetin and quercetin were potent inhibitors with the IC50 values less than 500 microM. The 2,3-double bond, 5-OH, the linkage of the B ring at the 3 position, and the hydroxyl substitution on the B ring enhanced the inhibitory activity, while 3-OH reduced it.
Topics: Animals; Enzyme Inhibitors; Flavonoids; Glycoside Hydrolase Inhibitors; Intestine, Small; Kinetics; Molecular Structure; Pancreas; Rats; Saccharomyces cerevisiae; Swine; alpha-Amylases; alpha-Glucosidases
PubMed: 16802696
DOI: 10.3177/jnsv.52.149 -
International Journal of Molecular... Oct 2019Amylases are probably the best studied glycoside hydrolases and have a huge biotechnological value for industrial processes on starch. Multiple amylases from fungi and...
Amylases are probably the best studied glycoside hydrolases and have a huge biotechnological value for industrial processes on starch. Multiple amylases from fungi and microbes are currently in use. Whereas bacterial amylases are well suited for many industrial processes due to their high stability, fungal amylases are recognized as safe and are preferred in the food industry, although they lack the pH tolerance and stability of their bacterial counterparts. Here, we describe three amylases, two of which have a broad pH spectrum extending to pH 8 and higher stability well suited for a broad set of industrial applications. These enzymes have the characteristic GH13 α-amylase fold with a central (β/α)-domain, an insertion domain with the canonical calcium binding site and a C-terminal β-sandwich domain. The active site was identified based on the binding of the inhibitor acarbose in form of a transglycosylation product, in the amylases from and . The three amylases have shortened loops flanking the nonreducing end of the substrate binding cleft, creating a more open crevice. Moreover, a potential novel binding site in the C-terminal domain of the enzyme was identified, which might be part of a starch interaction site. In addition, amylase presented a successful example of using the microseed matrix screening technique to significantly speed-up crystallization.
Topics: Amylases; Binding Sites; Catalytic Domain; Enzyme Activation; Enzyme Stability; Fungi; Glucose; Glycosylation; Hydrogen-Ion Concentration; Models, Molecular; Molecular Conformation; Protein Binding; Structure-Activity Relationship; alpha-Amylases
PubMed: 31623309
DOI: 10.3390/ijms20194902