Effect of Metal Ions, EDTA and Sulfhydryl Reagents on Soybean Amylase Activity

2011 ◽  
Vol 6 (3) ◽  
pp. 282-290 ◽  
Author(s):  
Om Prakash ◽  
Nivedita Jaiswal ◽  
Rajesh Kumar Pand
Keyword(s):  
Metal Ions ◽  
Amylase Activity ◽  
Sulfhydryl Reagents

Purification and Characterization of Thermostable α-Amylase from Soil Bacterium Bacillus sp.

2021 ◽  
Vol 28 ◽  
Author(s):  
Barış Enez
Keyword(s):  
Metal Ions ◽  
Amylase Activity ◽  
Low Cost ◽  
Sodium Dodecyl ◽  
Tween 20 ◽  
Bacillus Sp ◽  
Wide Range ◽  
Bacterium Bacillus ◽  
Triton X

Background: Amylases are used in several industrial and biotechnological sectors, including those producing textiles, detergents, paper and bakery products. Objective: This study aimed to purify an industrially important α-amylase from Bacillus sp. For this purpose, a single and rapid α-amylase purification was performed using the starch affinity method. Methods: Characterization of the purified enzyme was determined by investigating temperature, pH stability, detergents, and metal ions. Results: The purification coefficient of 29.8-fold with a yield of 9.2% was found. The molecular weight of the purified α-amylase was determined to be 53 kDa by SDS-PAGE, and thermostability was confirmed with 100% activity at 30ºC and 40ºC after 1 h. The purified enzyme was stable over a wide range of pH values, with optimum activity at pH 6.0, 7.0 and 8.0 after 2 h. The study also investigated the effects of the metal ions and detergents on the purified amylase and found that Mg2+ and Ca2+ ions were the activators of the enzyme, while Zn2+, Co2+ and Na+ ions decreased the activity. Furthermore, Hg2+ indicated complete inhibition of amylase activity. The detergents Triton X-100 and Tween 20 increased the α-amylase activity, while sodium dodecyl sulfate inhibited the activity. Conclusion: The purified α-amylase obtained from Bacillus sp. is considered to be environmentally friendly, can be processed in a short time, and has a low cost.

Effects of Metal Ions on Determination ofβ-Amylase Activity with 3,5-Dinitrosalicylic Acid

1978 ◽  
Vol 42 (12) ◽  
pp. 2393-2394
Author(s):  
Ryu Shinke ◽  
Sayoko Mizuno ◽  
Kenji Aoki ◽  
Hiroshi Nishira
Keyword(s):  
Metal Ions ◽  
Amylase Activity

scholarly journals Impact of Metal Ion Substitution on the Activity and Stability of Saccharifying Raw Starch Digesting Amylase from Aspergillus carbonarius

2020 ◽  
pp. 1-11
Author(s):  
Tochukwu Nwamaka Nwagu ◽  
Hideki Aoyagi ◽  
Bartholomew Okolo
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Amylase Activity ◽  
Chelating Agent ◽  
Limiting Factor ◽  
Aspergillus Carbonarius ◽  
Inhibition Rate ◽  
Raw Starch ◽  
Ion Substitution ◽  
The Stability

Though raw starch digesting amylases can be utilized in numerous bioprocesses, poor activity and stability remain a limiting factor.  In this study, the effect of metal ion substitution on the activity and stability of the RSDA from Aspergillus carbonarius was investigated. The amylase was inactivated using the chelating agent ethylene di aminotetraacetic acid (EDTA) and reactivated using different metal ions. The effect of different metal ions on the reactivation of the amylase activity was investigated. Impact of the metal ions on the stability of the amylase was also studied. Kinetic constants of the native enzyme were compared to the metal reactivated holoenzyme. Most efficient was 5 mM concentration of Co2+ with 94.6% activity recovery. Others included 5 mM Zn2+ (77.7%) and 5 mM Ca2+ (68.7%). Incubating the Co2+ activated amylase in 10 mM Mn2+ further stimulated the activity of the amylase to 136.7%. Compared to the metal ions tested, Mn2+ had the most stabilizing effect on the amylase; the amylase exhibited 148.2% and 136.5% activity at 70ºC and 80ºC respectively in the presence of 5 mM Mn2+. Ca2+ inhibited the amylase activity and inhibition rate increased with increasing concentration of Ca2+ concentrations. Km of the reactivated amylase was 0.18 mg/ml.

HREM Study of electron-induced surface radiation damage in ReO3

1991 ◽  
Vol 49 ◽  
pp. 636-637
Author(s):  
R. Ai ◽  
H.-J. Fan ◽  
L. D. Marks
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Metal Oxides ◽  
Electron Irradiation ◽  
Transition Metal Oxides ◽  
Carbon Film ◽  
Transition Metal Ions ◽  
Surface Radiation ◽  
Valence Transition ◽  
Electron Microscopes

It has been known for a long time that electron irradiation induces damage in maximal valence transition metal oxides such as TiO2, V2O5, and WO3, of which transition metal ions have an empty d-shell. This type of damage is excited by electronic transition and can be explained by the Knoteck-Feibelman mechanism (K-F mechanism). Although the K-F mechanism predicts that no damage should occur in transition metal oxides of which the transition metal ions have a partially filled d-shell, namely submaximal valence transition metal oxides, our recent study on ReO3 shows that submaximal valence transition metal oxides undergo damage during electron irradiation.ReO3 has a nearly cubic structure and contains a single unit in its cell: a = 3.73 Å, and α = 89°34'. TEM specimens were prepared by depositing dry powders onto a holey carbon film supported on a copper grid. Specimens were examined in Hitachi H-9000 and UHV H-9000 electron microscopes both operated at 300 keV accelerating voltage. The electron beam flux was maintained at about 10 A/cm2 during the observation.

ELNES of Iron Compounds

1990 ◽  
Vol 48 (2) ◽  
pp. 28-29
Author(s):  
Hiroki Kurata ◽  
Kazuhiro Nagai ◽  
Seiji Isoda ◽  
Takashi Kobayashi
Keyword(s):  
Energy Loss ◽  
Metal Ions ◽  
Energy Resolution ◽  
Transition Metal Oxides ◽  
Local Symmetry ◽  
Iron Compounds ◽  
Fine Structures ◽  
Electron Energy Loss ◽  
Fe Ions ◽  
Electron Energy Loss Spectra

Electron energy loss spectra of transition metal oxides, which show various fine structures in inner shell edges, have been extensively studied. These structures and their positions are related to the oxidation state of metal ions. In this sence an influence of anions coordinated with the metal ions is very interesting. In the present work, we have investigated the energy loss near-edge structures (ELNES) of some iron compounds, i.e. oxides, chlorides, fluorides and potassium cyanides. In these compounds, Fe ions (Fe2+ or Fe3+) are octahedrally surrounded by six ligand anions and this means that the local symmetry around each iron is almost isotropic.EELS spectra were obtained using a JEM-2000FX with a Gatan Model-666 PEELS. The energy resolution was about leV which was mainly due to the energy spread of LaB6 -filament. The threshole energies of each edges were measured using a voltage scan module which was calibrated by setting the Ni L3 peak in NiO to an energy value of 853 eV.

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