scholarly journals Purification and Interaction of β-amylase from Dioscorea alata (Water Yam) with Epicatechin

Author(s):  
M. A. Fadunsin ◽  
O. A. T. Ebuehi ◽  
I. S. Akande ◽  
A. O. Kolawole

β-amylase is an enzyme that hydrolyzes the α-1,4-glucan bonds from the non-reducing ends of starch and other carbohydrate polymers reducing it to maltose units. Maltose has much application with food processing and pharmaceutical industries. The enzyme was purified to apparent homogeneity with a monomeric molecular weight of 30.1 kDa based on SDS-PAGE. The binding Constant (Ka), Kd ΔH, ΔS and ΔG values were 1.53´103Lmol-1 ,3.12x10-4Lmol-1, 19.35kJmol-1, 56.67Jmol-1K-1, and -18.17kJmol-1 respectively. The binding profile of β-amylase with epicatechin was spontaneous with a stoichiometric ratio of 2:1. Hydrophobic bonding played a major role in stabilizing the β-amylase-ligand complex. The mode of reaction was by static quenching. It further dictates that the binding reaction is entropy driven. The inhibitory effect of this plant polyphenols on β-Amylase might contribute to the regulation of β-Amylase activity in plants.

2020 ◽  
Author(s):  
moromoke ajisope fadunsin ◽  
osaretin albert ebuehi ◽  
idowu akande ◽  
olawale raimi ◽  
oluseyi ayodele kolawole

Abstract Water yam (Dioscorea alata) β-amylase was isolated and purified to apparent homogeneity. The enzyme was found to be monomeric with a molecular weight of 30.1 kDa based on SDS-PAGE and 31.0 kDa based on non-denaturation gel filtration. The enzyme readily hydrolyzed soluble starch, amylose, amylopectin and glycogen. The enzyme was stable over a wide range of pHs (4 - 8). The enzyme has a Km, of 2.24 mg/ml for soluble starch. Activation energy (Ea) for catalysis by β-amylase at 25 0C was 6.45 kcal/mol. β-amylase Contains high content of both acidic and hydrophobic amino acid but low in arginine and histidine. The activation energy (Ea), half-life, free energy change (ΔG‡), enthalpy change (ΔH‡), and entropy change (ΔS‡) for inactivation were 13.92 kcal/mol, 41.25 min, 20.89 kcal/mol, 13.30 kcal/mol and -24.25 cal/mol/K, respectively. The binding profile of β-amylase with epicatechin, quercetin, rutin and gallic acid were all spontaneous with stoichiometric ratio of 1:1. Hydrophobic bonding played a major role in stabilizing the β-amylase-ligand complex. Sodium alginate immobilization of the enzyme improved the Optimum temperature from 40 to 50 0C and changed the optimum pH from 5.0 to 6.0 with retainment up to 67 % activity after 5 cycles of usage. The enzyme would be of importance in manufacturing company based on the kinetics and other parameters reported in this study.


1996 ◽  
Vol 76 (06) ◽  
pp. 0993-0997
Author(s):  
Zhao-Yan Li ◽  
Xiao-Wei Wu ◽  
Tie-Fu Yu ◽  
Eric C-Y Lian

SummaryBy means of CM-Sephadex C-25, DEAE-Sephadex A-50, Sephadex G-200, and Sephadex G-75 chromatographies, a lupus anticoagulant like protein (LALP) from Agkistrodon halys brevicaudus was purified. On SDS-PAGE, the purified LALP had a molecular weight of 25,500 daltons under non-reducing condition and 15,000 daltons under reducing condition. The isoelectric point was pH 5.6. Its N terminal amino acid sequencing revealed a mixture of 2 sequences: DCP(P/S)(D/G)WSSYEGH(C/R)Q(Q/K). It was devoid of phospho-lipaseA, fibrino(geno)lytic, 5′-nucleotidase, L-amino acid oxidase, phosphomonoesterase, phosphodiesterase and thrombin-like activities, which were found in crude venom. In the presence of LALP, PT, aPTT, and dRVVT of human plasma were markedly prolonged and its effects were concentration-dependent but time-independent. The inhibitory effect of LALP on the plasma clotting time was enhanced by decreasing phospholipid concentration in TTI test. The individual clotting factor activity was not affected by LALP when higher dilutions of LALP-plasma mixture were used for assay. Russell’s viper venom time was shortened when high phospholipid confirmatory reagent was used. Therefore, the protein has lupus anticoagulant property.


2013 ◽  
Vol 14 (1) ◽  
Author(s):  
Budiasih Wahyuntari ◽  
Martinus Nicoadi Tekol Tekol

Penghambat alfa amilase adalah salah satu komponen dalam suplemen makanan yang telah lama digunakan untuk terapi kegemukan karena penghambat amilase mempengaruhi metabolisme karbohidrat dalam sistem pencernaan. Sejumlah peneliti melaporkan terdapat dua grup penghambat amilase, yaitu protein dan non protein. Penghambat protein dilaporkan terdapat dalam kelompok kacang-kacangan dan biji-bijian. Tujuan penelitian ini adalah untuk mengisolasi penghambat protein yang terdapat dalam kacang hijau dan kedele. Kacang hijau dan kedele merupakan kacang-kacangan yang penting dalam makanan popular di Indonesia. Penghambat protein diendapkan dengan konsentrasi bertingkat garam ammonium sulfat [(NH)4SO4] dari 30-70%. Penghambat protein diuji terhadap amilase saliva manusia (HSA) danamilase pankreas babi (PPA), serta kestabilannya terhadap pemanasan pada 100oC selama 30 menit. Hasil penelitian menunjukkan bahwa semua endapan jenuh dari semua konsentrasi amonium sulfat yang diuji menghambat PPA, tetapi tidak semua endapan jenuh tersebut dapatmenghambat HSA. Hanya semua endapan jenuh (NH)4SO4 dari kacang hijau yang dapat menghambat HSA, dan penghambatan tertinggi terhadap HSA adalah endapan jenuh (NH)4SO4 50%. Endapan jenuh (NH)4SO4 40 % dari kedele putih dan endapan jenuh (NH)4SO4 60% dari kedele hitam dengan masing-masing penghambatan 98.67; 26.86 and27.63%. Endapan jenuh (NH)4SO4 60-70% dari kacang hijau, 50% dari kedele putih dan 50% dari kedele hitam menghambat PPA 100%. Pemanasan penghambat pada 100oC selama 30 menit hampir tidak mempengaruhi penghambatannya terhadap PPA. Profil protein juga diamati menggunakan analisis SDS/PAGE.


The Consistent Mixed Tank Reactor is widely used in chemical processing plants, food processing industries and in pharmaceutical industries. The Consistent Mixed Tank Reactor is a nonlinear process. If any of inputs to the process or any parameters in the process gets changed means the entire working of the plant gets changed. And also it leads to decrease the accuracy of the final or end product. So, to get required end result the accuracy developed in the Consistent Mixed Tank Reactor process where the tank is in running condition need to be identified and necessary steps should be taken to avoid those fault. There are several fault diagnosis methods available. Among those techniques, the Neural System Prescient Controller can be utilized to identify and diagnose the error present inside Consistent Mixed Tank Reactor tank. From the Neural System Prescient Controller, the servo response is obtained to understand clearly about the behavior of the Consistent Mixed Tank Reactor tank process. Thus, by selecting suitable controlling techniques the accuracy of the desired product can be obtained in Consistent Mixed Tank Reactor tank.


2020 ◽  
Vol 49 (4) ◽  
pp. 415-423
Author(s):  
B. Baráti-Deák ◽  
Cs. Mohácsi-Farkas ◽  
Á. Belák

Bacterial strains with inhibitory effect on Salmonella Hartford, Listeria monocytogenes, Yersinia enterocolitica, and Escherichia coli, respectively, were isolated. Out of the 64 bacteria originated from food processing environments, 20 could inhibit at least one of the tested pathogens, and it was proved that growth decline of the pathogenic bacteria was more remarkable by co-culturing than by using cell-free supernatants of the isolates. Seven different genera (Pseudomonas, Bacillus, Paenibacillus, Macrococcus, Staphylococcus, Serratia, and Rothia) reduced the pathogens’ growth during the time period of analysis, and the strongest inhibitory effect was observed after 24 h between 15 and 30 °C. Sensitivity of the tested human pathogenic bacteria against the inhibitory strains was distinct, as Y. enterocolitica could be inhibited by numerous isolates, while S. Hartford proved to be the most resistant. Our results reveal that the isolated bacteria or their excreted metabolites could hinder pathogen growth when used in sufficient quantities.


1979 ◽  
Author(s):  
Junki Takamatsu ◽  
Kanji Oqata ◽  
Tadashi Kamiya ◽  
Katsuo Koie ◽  
Takagi Takashi ◽  
...  

Six individuals in 3 generations of Japanese family had prolonged thrombin clotting time, but no history of hemorrhagic or thrombotic disease. Very low fibrinogen levels were obtained by thrombin clottable protein, while immunological procedures gave normal values of fibrinogen. The serum contained 40-80μg/ml of unclottable fibrinogen related antigens. The patients’ plasma had an inhibitory effect on the fibrin formation in normal plasma. Major defect of this fibrinogen was a delayed aggregation of fibrin monomers.On CM-chromatography (CM-52) of the S-carboxymethylated fibrinogen, three different γ-chains, named γx, γL and γR, were separated. They did not differ in their electrophoretic mobilities in SDS-PAGE, but were distinguishable in PAGE containing 8M urea. Moreover, the amino acid compositions and tryptic peptide mappings of each chain revealed a little difference from those of normal fibrinogen γ chains, suggesting the difference in amino acid substitution or oligosaccharide chain structure.Based on these findings, we designated this fibrinogen as fibrinogen Nagoya; its possible identity without other dysfibrinogenemia has not been excluded.


2004 ◽  
Vol 22 (SI - Chem. Reactions in Foods V) ◽  
pp. S303-S305 ◽  
Author(s):  
O. Krejčová ◽  
E. Šviráková ◽  
J. Dobiáš ◽  
M. Plocková

Active packaging systems based on the application of packaging materials with incorporated and/or immobilized antimicrobial agents provides one of promising trends in food processing. The object of this work was to test the effect of polyethylene (LDPE) packaging film treated with lacquer containing 5% (w/w) Nisaplin<sup>®</sup> on the growth of lactic acid bacteria, aerobic sporeforming bacteria, Bacillus cereus and on the changes of total count of bacteria in packaged meat products and processed cheese. Peaces of cheese in contact with nisin treated film were stored at 21°C for 0, 7, and 28 days. The obtained results confirmed significant inhibitory effect of such packaging system against aerobic sporeforming bacteria, when the decrease of above mentioned bacteria contamination up to four logarithmic cycles were determined. In contact with sliced salami the significant decrease of total bacteria as well as lactic acid bacteria counts were found. During storage of packaged salami for two weeks at 5°C the total bacteria count on the surface of product in contact with the package dropped by more than one logarithmic cycles, present lactic bacteria were inhibited by more than two logarithmic cycles.


1990 ◽  
Vol 267 (2) ◽  
pp. 509-515 ◽  
Author(s):  
N M Hooper ◽  
J Hryszko ◽  
A J Turner

Aminopeptidase P (EC 3.4.11.9) was solubilized from pig kidney membranes with bacterial phosphatidylinositol-specific phospholipase C (PI-PLC) and then purified by a combination of anion-exchange and hydrophobic-interaction chromatographies. Contaminating peptidase activities were removed by selective affinity chromatography. The purified enzyme was apparently homogeneous on SDS/PAGE with an Mr of 91,000. Enzymic deglycosylation revealed that aminopeptidase P is a glycoprotein, with up to 25% by weight of the protein being due to the presence of N-linked sugars. The phospholipase-solubilized aminopeptidase P was recognized by an antiserum to the cross-reacting determinant (CRD) characteristic of the glycosyl-phosphatidylinositol anchor. This recognition was abolished by mild acid treatment or deamination with HNO2, indicating that the CRD was due exclusively to the inositol 1,2-cyclic phosphate ring epitope generated by the action of PI-PLC. The activity of aminopeptidase P was inhibited by chelating agents and was stimulated by Mn2+ or Co2+ ions, confirming the metallo-enzyme nature of this peptidase. Selective inhibitors of other aminopeptidases (actinonin, amastatin, bestatin and puromycin) had little or no inhibitory effect.


1984 ◽  
Vol 159 (6) ◽  
pp. 1653-1668 ◽  
Author(s):  
J D Vassalli ◽  
J M Dayer ◽  
A Wohlwend ◽  
D Belin

The plasminogen activator (PA) produced by freshly purified human monocytes-macrophages and histiocytic, lymphoma-derived U 937 cells was analyzed by zymography after sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and found to migrate with an apparent Mr of 55,000, identical to that of urokinase (Uk). By immunoprecipitation with antibodies specific for the two different types of PA, the enzyme was shown to be immunologically related to urokinase, and not to tissue PA. Urokinase was secreted in the form of the inactive Mr 55,000 zymogen prourokinase , and could be converted to the active Mr 55,000 enzyme by limited proteolysis with plasmin. Conditioned media from cultures of U 937 cells and monocytes-macrophages inhibited the fibrinolytic activity of exogenously added urokinase. Using [125I]-labeled urokinase we observed the formation of an enzyme-ligand complex, which was not dissociated by boiling in SDS and migrated with an apparent Mr 40,000 daltons higher than the free enzyme; since complexed urokinase was functionally inactivated as a PA, the ligand is an inhibitor of urokinase. This inhibitor is different from fibroblast-produced protease- nexin , in that it did not interact with thrombin. These results suggest that plasminogen activation by mononuclear phagocytes can be modulated through the secretion of both (pro)enzyme and a specific inhibitor.


2013 ◽  
Vol 49 (2) ◽  
pp. 351-358 ◽  
Author(s):  
Flávia Angélica Másquio Fiorentino ◽  
Marcos Antonio Corrêa ◽  
Hérida Regina Nunes Salgado

Chlorhexidine (CHX) is a broad-spectrum antiseptic that is used in many topical pharmaceutical formulations. Because there is no official microbiological assay reported in the literature that is used to quantify CHX, this paper reports the development and validation of a simple, sensitive, accurate and reproducible agar diffusion method for the dosage of chlorhexidine digluconate (CHX-D) in an aqueous solution. The assay is based on the inhibitory effect of CHX-D upon the strain of Staphylococcus aureus ATCC 25923, which is used as the test microorganism. The design 3x3 parallel-line model was used. The results were treated statistically by analysis of variance (ANOVA), and they were excellent in terms of linearity (r = 0.9999), presenting a significant regression between the zone diameter of growth inhibition and the logarithm of the concentration within the range of 0.5 to 4.5%. The results obtained were precise, having relative standard deviations (RSD) for intra-day and inter-day precision of 2.03% and 2.94%, respectively. The accuracy was 99.03%. The method proved to be very useful and appropriate for the microbiological dosage of CHX-D in pharmaceutical formulations; it might also be used for routine drug analysis during quality control in pharmaceutical industries.


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