Showing papers on "Amylase published in 2017"

Mechanisms of starch digestion by α-amylase-Structural basis for kinetic properties.

Abstract: Recent studies of the mechanisms determining the rate and extent of starch digestion by α-amylase are reviewed in the light of current widely-used classifications for (a) the proportions of rapidly-digestible (RDS), slowly-digestible (SDS), and resistant starch (RS) based on in vitro digestibility, and (b) the types of resistant starch (RS 1,2,3,4…) based on physical and/or chemical form. Based on methodological advances and new mechanistic insights, it is proposed that both classification systems should be modified. Kinetic analysis of digestion profiles provides a robust set of parameters that should replace the classification of starch as a combination of RDS, SDS, and RS from a single enzyme digestion experiment. This should involve determination of the minimum number of kinetic processes needed to describe the full digestion profile, together with the proportion of starch involved in each process, and the kinetic properties of each process. The current classification of resistant starch types as RS1,2,3,4 should be replaced by one which recognizes the essential kinetic nature of RS (enzyme digestion rate vs. small intestinal passage rate), and that there are two fundamental origins for resistance based on (i) rate-determining access/binding of enzyme to substrate and (ii) rate-determining conversion of substrate to product once bound.

Improving Bread Quality with the Application of a Newly Purified Thermostable α-Amylase from Rhizopus oryzae FSIS4

Abstract: A new thermostable α-amylase from Rhizopus oryzae FSIS4 was purified for first time and recovered in a single step using a three-phase partitioning (TPP) system. The fungal α-amylase, at a concentration of 1.936 U per kg of flour, was used in bread-making and compared to the commercial enzyme. The results showed a significant effect of the recovered α-amylase in the prepared bread and allowed us to improve the quality of the bread. The study indicated clearly that the recovered α-amylase is a potential candidate for future applications in the bread-making industry and in other food biotechnology applications.

Biotechnological Processes in Microbial Amylase Production.

Abstract: Amylase is an important and indispensable enzyme that plays a pivotal role in the field of biotechnology. It is produced mainly from microbial sources and is used in many industries. Industrial sectors with top-down and bottom-up approaches are currently focusing on improving microbial amylase production levels by implementing bioengineering technologies. The further support of energy consumption studies, such as those on thermodynamics, pinch technology, and environment-friendly technologies, has hastened the large-scale production of the enzyme. Herein, the importance of microbial (bacteria and fungi) amylase is discussed along with its production methods from the laboratory to industrial scales.

Transcription Factor AREB2 Is Involved in Soluble Sugar Accumulation by Activating Sugar Transporter and Amylase Genes

Abstract: Sugars play important roles in plant growth and development, crop yield and quality, as well as responses to abiotic stresses. Abscisic acid (ABA) is a multifunctional hormone. However, the exact mechanism by which ABA regulates sugar accumulation is largely unknown in plants. Here, we tested the expression profile of several sugar transporter and amylase genes in response to ABA treatment. MdSUT2 and MdAREB2 were isolated and genetically transformed into apple (Malus domestica) to investigate their roles in ABA-induced sugar accumulation. The MdAREB2 transcription factor was found to bind to the promoters of the sugar transporter and amylase genes and activate their expression. Both MdAREB2 and MdSUT2 transgenic plants produced more soluble sugars than controls. Furthermore, MdAREB2 promoted the accumulation of sucrose and soluble sugars in an MdSUT2-dependent manner. Our results demonstrate that the ABA-responsive transcription factor MdAREB2 directly activates the expression of amylase and sugar transporter genes to promote soluble sugar accumulation, suggesting a mechanism by which ABA regulates sugar accumulation in plants.

Antidiabetic potential: in vitro inhibition effects of some natural phenolic compounds on α-glycosidase and α-amylase enzymes.

Abstract: α-Glycosidase is a catalytic enzyme and it destroys the complex carbohydrates into simple absorbable sugar units. The natural phenolic compounds were tested for their antidiabetic properties as α-glycosidase and α-amylase inhibitors. The phenolic compounds investigated in this study have been used as antidiabetic common medicines. This paper aimed to consider their capability to inhibit α-amylase and α-glycosidase, two significant enzymes defined in serum glucose adjustment. These examination recorded impressive inhibition profiles with IC50 values in the range of 137.36–737.23 nM against α-amylase and 29.01–157.96 nM against α-glycosidase.

Influence of cold plasma on the enzymatic activity in germinating mung beans (Vigna radiate)

Abstract: The aim of this work is to study the effect of the cold plasma in the enhancement of mung bean seeds germination. To investigate changes in the seeds we have applied two plasma power levels and three exposure time intervals. Results showed that, cold plasma significantly increased the germination rate by 36.2%, radical root length by 20% and conductivity of seeds by 102% when compared to the control samples. The surface etching caused by the plasma species increased the seeds coat conductivity and apparently reduced the contact angle making surface more hydrophilic. There is increase in soluble sugars and proteins after the treatment. We also observed increase in hydrolytic enzymes activity like amylase, protease and phytase after the treatment. The decrease in anti-nutritional properties like trypsin inhibition activity and phytic acid showed a positive effect of cold plasma treatment. Thus, cold plasma application can significantly benefit the seed germination during drought conditions.

Production and Partial Characterization of α-Amylase Enzyme from Bacillus sp. BCC 01-50 and Potential Applications

Abstract: Amylase is an industrially important enzyme and applied in many industrial processes such as saccharification of starchy materials, food, pharmaceutical, detergent, and textile industries. This research work deals with the optimization of fermentation conditions for α-amylase production from thermophilic bacterial strain Bacillus sp. BCC 01-50 and characterization of crude amylase. The time profile of bacterial growth and amylase production was investigated in synthetic medium and maximum enzyme titer was observed after 60 h. In addition, effects of different carbon sources were tested as a substrate for amylase production and molasses was found to be the best. Various organic and inorganic compounds, potassium nitrate, ammonium chloride, sodium nitrate, urea, yeast extract, tryptone, beef extract, and peptone, were used and beef extract was found to be the best among the nitrogen sources used. Temperature, pH, agitation speed, and size of inoculum were also optimized. Highest enzyme activity was obtained when the strain was cultured in molasses medium for 60 h in shaking incubator (150 rpm) at 50°C and pH 8. Crude amylase showed maximal activity at pH 9 and 65°C. Enzyme remained stable in alkaline pH range 9-10 and 60–70°C. Crude amylase showed great potential for its application in detergent industry and saccharification of starchy materials.

Amylases: Characteristics and industrial applications

Abstract: Amylases are widely distributed in microbial, plant and animal kingdoms. They degrade starch and related polymers to yield products characteristic of individual amylolytic enzymes. Alpha amylase has been derived from several fungi, yeasts, bacteria and actinomycetes, however, enzymes from fungal and bacterial sources have dominated applications in industrial sectors. The pH dependence of amylase activity was assayed in a pH range of 4-11, using the standard reaction mixture. The optimum temperature for maximal Amylase activity was found to be 30-35 0C, after which the enzyme activity dropped. The addition of metals like Ca2+ and Mn2+ and Mg2+ increased the enzyme activity while a significant inhibitory effect on the protease activity was observed with Hg2+. Amylase from apple exhibited high efficiency for the removal of chocolate stains in combination with commercial detergent (Tide). The wash performance analysis of chocolate stains on cotton fabric showed an increase in reflectance with detergent and enzyme as compared to detergent only.

Isolation and Characterization of Thermophilic Bacteria from Geothermal Areas in Turkey and Preliminary Research on Biotechnologically Important Enzyme Production

Abstract: In this study, the isolation, identification and characterization of the thermophilic bacteria from different hot springs in Turkey were carried out by conventional (morphological, physiological and biochemical tests) and molecular methods (fatty acid methyl esters, GTG5-PCR and 16S rRNA sequencing). These thermophilic bacteria were then tested for their capability to produce enzymes such as lipase, protease, amylase and cellulase. O20 strain is a novel species according to identification studies. All of its isolates were capable of producing industrially valuable enzymes based on screening. In fact, most of them could produce at least two of these enzymes.

Amylases StAmy23, StBAM1 and StBAM9 regulate cold-induced sweetening of potato tubers in distinct ways.

Abstract: Cold-induced sweetening (CIS) in potato is detrimental to the quality of processed products. Conversion of starch to reducing sugars (RS) by amylases is considered one of the main pathways in CIS but is not well studied. The amylase genes StAmy23, StBAM1, and StBAM9 were studied for their functions in potato CIS. StAmy23 is localized in the cytoplasm, whereas StBAM1 and StBAM9 are targeted to the plastid stroma and starch granules, respectively. Genetic transformation of these amylases in potatoes by RNA interference showed that β-amylase activity could be decreased in cold-stored tubers by silencing of StBAM1 and collective silencing of StBAM1 and StBAM9. However, StBAM9 silencing did not decrease β-amylase activity. Silencing StBAM1 and StBAM9 caused starch accumulation and lower RS, which was more evident in simultaneously silenced lines, suggesting functional redundancy. Soluble starch content increased in RNAi-StBAM1 lines but decreased in RNAi-StBAM9 lines, suggesting that StBAM1 may regulate CIS by hydrolysing soluble starch and StBAM9 by directly acting on starch granules. Moreover, StBAM9 interacted with StBAM1 on the starch granules. StAmy23 silencing resulted in higher phytoglycogen and lower RS accumulation in cold-stored tubers, implying that StAmy23 regulates CIS by degrading cytosolic phytoglycogen. Our findings suggest that StAmy23, StBAM1, and StBAM9 function in potato CIS with varying levels of impact.

Rethinking the starch digestion hypothesis for AMY1 copy number variation in humans.

Abstract: Alpha-amylase exists across taxonomic kingdoms with a deep evolutionary history of gene duplications that resulted in several α-amylase paralogs. Copy number variation (CNV) in the salivary α-amylase gene (AMY1) exists in many taxa, but among primates, humans appear to have higher average AMY1 copies than nonhuman primates. Additionally, AMY1 CNV in humans has been associated with starch content of diets, and one known function of α-amylase is its involvement in starch digestion. Thus high AMY1 CNV is considered to result from selection favoring more efficient starch digestion in the Homo lineage. Here, we present several lines of evidence that challenge the hypothesis that increased AMY1 CNV is an adaptation to starch consumption. We observe that α- amylase plays a very limited role in starch digestion, with additional steps required for starch digestion and glucose metabolism. Specifically, we note that α-amylase hydrolysis only produces a minute amount of free glucose with further enzymatic digestion and glucose absorption being rate-limiting steps for glucose availability. Indeed α-amylase is nonessential for starch digestion since sucrase-isomaltase and maltase-glucoamylase can hydrolyze whole starch granules while releasing glucose. While higher AMY1 CN and CNV among human populations may result from natural selection, existing evidence does not support starch digestion as the major selective force. We report that in humans α-amylase is expressed in several other tissues where it may have potential roles of evolutionary significance.

Functional expression of a novel α-amylase from Antarctic psychrotolerant fungus for baking industry and its magnetic immobilization

Abstract: α-Amylase plays a pivotal role in a broad range of industrial processes. To meet increasing demands of biocatalytic tasks, considerable efforts have been made to isolate enzymes produced by extremophiles. However, the relevant data of α-amylases from cold-adapted fungi are still insufficient. In addition, bread quality presents a particular interest due to its high consummation. Thus developing amylases to improve textural properties could combine health benefits with good sensory properties. Furthermore, iron oxide nanoparticles provide an economical and convenient method for separation of biomacromolecules. In order to maximize the catalytic efficiency of α-amylase and support further applications, a comprehensive characterization of magnetic immobilization of α-amylase is crucial and needed. A novel α-amylase (AmyA1) containing an open reading frame of 1482 bp was cloned from Antarctic psychrotolerant fungus G. pannorum and then expressed in the newly constructed Aspergillus oryzae system. The purified recombinant AmyA1 was approximate 52 kDa. AmyA1 was optimally active at pH 5.0 and 40 °C, and retained over 20% of maximal activity at 0–20 °C. The K m and V max values toward soluble starch were 2.51 mg/mL and 8.24 × 10−2 mg/(mL min) respectively, with specific activity of 12.8 × 103 U/mg. AmyA1 presented broad substrate specificity, and the main hydrolysis products were glucose, maltose, and maltotetraose. The influence of AmyA1 on the quality of bread was further investigated. The application study shows a 26% increase in specific volume, 14.5% increase in cohesiveness and 14.1% decrease in gumminess in comparison with the control. AmyA1 was immobilized on magnetic nanoparticles and characterized. The immobilized enzyme showed improved thermostability and enhanced pH tolerance under neutral conditions. Also, magnetically immobilized AmyA1 can be easily recovered and reused for maximum utilization. A novel α-amylase (AmyA1) from Antarctic psychrotolerant fungus was cloned, heterologous expression in Aspergillus oryzae, and characterized. The detailed report of the enzymatic properties of AmyA1 gives new insights into fungal cold-adapted amylase. Application study showed potential value of AmyA1 in the food and starch fields. In addition, AmyA1 was immobilized on magnetic nanoparticles and characterized. The improved stability and longer service life of AmyA1 could potentially benefit industrial applications.

Impact of Liraglutide on Amylase, Lipase, and Acute Pancreatitis in Participants With Overweight/Obesity and Normoglycemia, Prediabetes, or Type 2 Diabetes: Secondary Analyses of Pooled Data From the SCALE Clinical Development Program

Abstract: OBJECTIVE To describe amylase/lipase activity levels and events of acute pancreatitis (AP) in the SCALE (Satiety and Clinical Adiposity—Liraglutide Evidence in individuals with and without diabetes) weight-management trials. RESEARCH DESIGN AND METHODS Secondary analyses were performed on pooled data from four trials (N = 5,358 with BMI ≥30, or 27 to RESULTS Over 56 weeks, liraglutide 3.0 mg versus placebo was associated with increases in mean levels of 7% (amylase) and 31% (lipase), respectively. Similar changes in amylase/lipase levels were observed with liraglutide 1.8 mg. More participants receiving liraglutide 3.0 mg versus placebo experienced amylase (9.4% vs. 5.9%) and lipase (43.5% vs. 15.1%) elevations greater than or equal to the upper limit of normal (ULN); few had elevations ≥3 × ULN for amylase ( CONCLUSIONS Liraglutide resulted in dose-independent, reversible increases in amylase/lipase activity, unrelated to baseline characteristics, not predicting AP onset. Gallstones possibly contributed to 50% of AP cases. Data provide no basis for amylase/lipase level monitoring in liraglutide treatment except in suspected AP.