scholarly journals The effects of macromolecular crowding and surface charge on the properties of an immobilized enzyme: activity, thermal stability, catalytic efficiency and reusability

RSC Advances ◽  
2017 ◽  
Vol 7 (60) ◽  
pp. 38028-38036 ◽  
Author(s):  
Qiong Yang ◽  
Bochu Wang ◽  
Zhi Zhang ◽  
Deshuai Lou ◽  
Jun Tan ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Enzyme Activity ◽  
Surface Charge ◽  
Immobilized Enzyme ◽  
Macromolecular Crowding ◽  
Catalytic Efficiency ◽  
Enzyme Molecule

The microenvironment around an immobilized enzyme molecule significantly influences the properties of the immobilized enzyme.

scholarly journals A Novel Process to Prepare Chitosan Macrospheres without Shrinkage and its Application to Immobilize β-Galactosidase

2009 ◽  
Vol 6 (4) ◽  
pp. 1211-1220 ◽  
Author(s):  
Su-Fang Sun ◽  
Yan Zhang
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Enzyme Activity ◽  
Immobilized Enzyme ◽  
Maximum Velocity ◽  
Glycerol Solution ◽  
New Process ◽  
Michaelis Constants ◽  
Activity Yield ◽  
Different Molecular Weight

A new process for the preparation of chitosan macrospheres, which was simple and practicable, was suggested in this paper and various chitosans with different molecular weight were used as materials to immobilize β-galactosidase and the chitosan macrospheres with the lowest molecular weight (500 000) was selected as enzyme immobilization carrier based on the highest enzyme activity. In order to overcome the shrinkage of chitosan during drying, the wet macrospheres obtained was treated by 30% glycerol solution for 1 h before drying and the results showed that the dried chitosan macrospheres obtained could keep almost the same structure as its wet form, which was very important for chitosan as enzyme carrier in industry. Finally, β-galactosidase from Aspergillus oryzae was immobilized on above dry chitosan macrospheres and a satisfactory result of the immobilized enzyme was obtained in enzyme activity yield, pH stability, thermal stability, operational stability, Michaelis constants Kmand the maximum velocity (Vm)

scholarly journals Macromolecular Crowding Enhances Catalytic Efficiency and Stability of α-Amylase

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Jay Kant Yadav
Keyword(s):  
Thermal Stability ◽  
Relative Effectiveness ◽  
Macromolecular Crowding ◽  
Catalytic Efficiency ◽  
Crowding Effect ◽  
Functional Attributes ◽  
Marginal Change ◽  
High Concentrations ◽  
Thermal Stability Of

In the present study an attempt was made to investigate the macromolecular crowding effect on functional attributes of α-amylase. High concentrations of sugar based cosolvents, (e.g., trehalose, sucrose, sorbitol, and glycerol) were used to mimic the macromolecular crowding environment (of cellular milieu) under in vitro conditions. To assess the effect of macromolecular crowding, the activity and structural properties of the enzyme were evaluated in the presence of different concentrations of the above cosolvents. Based on the results it is suggested that the macromolecular crowding significantly improves the catalytic efficiency of the enzyme with marginal change in the structure. Out of four cosolvents examined, trehalose was found to be the most effective in consistently enhancing thermal stability of the enzyme. Moreover, the relative effectiveness of the above cosolvents was found to be dependent on their concentration used.

scholarly journals Immobilization ofAspergillus Oryzae β-Galactosidase on Newly Prepared Porous Poly(GMA-ST)

2011 ◽  
Vol 8 (3) ◽  
pp. 1232-1237 ◽  
Author(s):  
Sun Sufang ◽  
Xu Xiaobing
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Scanning Electron Microscopy ◽  
Enzyme Activity ◽  
Kinetic Data ◽  
Immobilized Enzyme ◽  
Lauryl Alcohol ◽  
Optimum Conditions ◽  
Porous Poly ◽  
Scanning Electron

The macroporous and reactive carriers polyGMA-ST was synthesized simultaneously with a mixture of cyclohexanol and lauryl alcohol as liquid pore-forming agents and nano-calcium carbonate as solid one by bulk copolymerization. After the polymer was smashed, particles with diameters ranging 0.15 mm to 0.30 mm were taken as the carrier and the Scanning electron microscopy (SEM) micrographs were done to characterize its surface structure. Under the optimum conditions,β-galactosidaseAspergillus oryzaewas immobilized on the supporter obtained above, its enzyme activity could reach to 535.11U/g dry carrier and the activity recovery of the immobilizedβ-galactosidase was 79.63%. Meanwhile, the basic property and the kinetic data of the immobilized enzyme were determined and compared with those of the free enzyme and satisfactory results were obtained in pH stability, thermal stability and operational stability. The conclusion obtained here indicated that the ploy(GMA-co-ST) prepared concurrently with liquid and solid porogen was suitable to immobilize enzyme.

scholarly journals Enzyme activity and stability of lactase immobilized on two different supports: Calcium alginate and magnetic chitosan

2020 ◽  
Vol 16 (4) ◽  
pp. 413-417
Author(s):  
Farah Syafiqah Mohd Zawawi ◽  
Latiffah Karim ◽  
Siti Radhiah Omar ◽  
Asma’ Ali
Keyword(s):  
Thermal Stability ◽  
Enzyme Activity ◽  
Enzymatic Activity ◽  
Calcium Alginate ◽  
Lactose Intolerance ◽  
Immobilized Enzyme ◽  
Soluble Form ◽  
Optimum Temperature ◽  
Magnetic Chitosan ◽  
Important Enzyme

Lactase is a very important enzyme to cure lactose intolerance problem. However, it is naturally existing in soluble form and cannot be reused. The current study was performed to compare the productivity and stability of lactase immobilized on calcium alginate and magnetic chitosan. The reusability of immobilized enzyme was measured for 28 days. Thermal stability was measured at 27, 37, 50 and 70 ºC. Lactase immobilized on calcium alginate showed a better stability after 21 days where it retained up to 62% of enzyme activity. However, lactase on magnetic chitosan expresses a better thermal stability as it produced 6% more sugar than lactase on calcium alginate at the optimum temperature 50 ºC. Lactase immobilized on calcium alginate and magnetic chitosan showed significantly different enzymatic activity, stability, and reusability.

Effect of the hydrophilicity of the polymer matrix on immobilized α-chymotrypsin

1984 ◽  
Vol 49 (6) ◽  
pp. 1552-1556
Author(s):  
Minoru Kumakura ◽  
Isso Kaetsu
Keyword(s):  
Thermal Stability ◽  
Enzyme Activity ◽  
Pore Size ◽  
Polymer Matrix ◽  
Low Temperatures ◽  
Radiation Polymerization ◽  
Thermal Stability Of

α-Chymotrypsin was immobilized by radiation polymerization at low temperatures and the effect of the hydrophilicity of the polymer matrix on the enzyme activity and thermal stability was studied. The activity and thermal stability of immobilized chymotrypsin increased with the increasing hydrophilicity of the polymer matrix or monomer. The thermal stability was affected by the form and pore size of the polymer matrix; chymotrypsin immobilized on a soft-gel polymer matrix exhibited an enhanced thermal stability.

scholarly journals Effects of morphology and pore size of mesoporous silicas on the efficiency of an immobilized enzyme

RSC Advances ◽  
2021 ◽  
Vol 11 (17) ◽  
pp. 10010-10017
Author(s):  
Ping-Chung Kuo ◽  
Zhi-Xun Lin ◽  
Tzi-Yi Wu ◽  
Chun-Han Hsu ◽  
Hong-Ping Lin ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Mesoporous Silica ◽  
Pore Size ◽  
Immobilized Enzyme ◽  
Mesoporous Silicas ◽  
High Loading ◽  
Loading Capacity ◽  
Silica Films

Mesoporous silica films were used as supports with high loading capacity and enzyme activity.

Binding of 3-phosphoglycerate leads to both activation and stabilisation of ADP-glucose pyrophosphorylase from apple leaves

2005 ◽  
Vol 32 (9) ◽  
pp. 839
Author(s):  
Rui Zhou ◽  
Lailiang Cheng
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Enzyme Activity ◽  
Inorganic Phosphate ◽  
Thermal Inactivation ◽  
Specific Activity ◽  
Apple Leaves ◽  
Apparent Homogeneity ◽  
Adp Glucose Pyrophosphorylase ◽  
High Concentrations

Apple leaf ADP-glucose pyrophosphorylase was purified 1436-fold to apparent homogeneity with a specific activity of 58.9 units mg–1. The enzyme was activated by 3-phosphoglycerate (PGA) and inhibited by inorganic phosphate (Pi) in the ADPG synthesis direction. In the pyrophosphorolytic direction, however, high concentrations of PGA (> 2.5 mm) inhibited the enzyme activity. The enzyme was resistant to thermal inactivation with a T0.5 (temperature at which 50% of the enzyme activity is lost after 5 min incubation) of 52°C. Incubation with 2 mm PGA or 2 mm Pi increased T0.5 to 68°C. Incubation with 2 mm dithiothreitol (DTT) decreased T0.5 to 42°C, whereas inclusion of 2 mm PGA in the DTT incubation maintained T0.5 at 52°C. DTT-induced decrease in thermal stability was accompanied by monomerisation of the small subunits. Presence of PGA in the DTT incubation did not alter the monomerisation of the small subunits of the enzyme induced by DTT. These findings indicate that binding of PGA renders apple leaf AGPase with a conformation that is not only more efficient in catalysis but also more stable to heat treatment. The physiological significance of the protective effect of PGA on thermal inactivation of AGPase is discussed.

scholarly journals Extracellular α-Galactosidase from Trichoderma sp. (WF-3): Optimization of Enzyme Production and Biochemical Characterization

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Aishwarya Singh Chauhan ◽  
Arunesh Kumar ◽  
Nikhat J. Siddiqi ◽  
B. Sharma
Keyword(s):  
Enzyme Activity ◽  
Enzyme Assay ◽  
Biochemical Characterization ◽  
Catalytic Efficiency ◽  
Culture Conditions ◽  
Significant Loss ◽  
Trichoderma Sp ◽  
Rate Of Reaction ◽  
Higher Temperature ◽  
Substrate Concentrations

Trichoderma spp. have been reported earlier for their excellent capacity of secreting extracellular α-galactosidase. This communication focuses on the optimization of culture conditions for optimal production of enzyme and its characterization. The evaluation of the effects of different enzyme assay parameters such as stability, pH, temperature, substrate concentrations, and incubation time on enzyme activity has been made. The most suitable buffer for enzyme assay was found to be citrate phosphate buffer (50 mM, pH 6.0) for optimal enzyme activity. This enzyme was fairly stable at higher temperature as it exhibited 72% activity at 60°C. The enzyme when incubated at room temperature up to two hours did not show any significant loss in activity. It followed Michaelis-Menten curve and showed direct relationship with varying substrate concentrations. Higher substrate concentration was not inhibitory to enzyme activity. The apparent Michaelis-Menten constant (Km), maximum rate of reaction (Vmax), Kcat, and catalytic efficiency values for this enzyme were calculated from the Lineweaver-Burk double reciprocal plot and were found to be 0.5 mM, 10 mM/s, 1.30 U mg−1, and 2.33 U mg−1 mM−1, respectively. This information would be helpful in understanding the biophysical and biochemical characteristics of extracellular α-galactosidase from other microbial sources.

Enantioselective Resolution of (R, S)-DMPM by a Adsorption-Covalent Crosslinked Esterase PAE07 from Pseudochrobactrum Asaccharolyticum WZZ003

2021 ◽  
Author(s):  
Mingpeng Zhou ◽  
Yuandan Xia ◽  
Hongjun Zhang ◽  
Xinjun Yu ◽  
Yinjun zhang
Keyword(s):  
Thermal Stability ◽  
Enzyme Activity ◽  
Sem Analysis ◽  
Optimal Conditions ◽  
Synthetic Resin ◽  
Adsorption Time ◽  
Enantioselective Resolution ◽  
Primary Amino ◽  
Repeated Use ◽  
Amino Resin

Abstract (R)-N-(2,6-dimethylphenyl) alanine ((R)-MAP-acid) is an important chiral intermediate of the Fungicide (R)-Metalaxyl. In this study, ten kinds of immobilized resins(XAD1180N, H103, HAD7HP, D3520, NKA, D101 , DM11,850 JinKai, Primary amino resin and 850 synthetic resin) were used to adsorption-covalent crosslinked esterase PAE07 for splitting (R, S)-DMPM. The resin D3520 with porous structure and hydrophobic polystyrene was selected for immobilization as the carrier, after optimization of the immobilization conditions, the enzyme load is 20:1 (mg/g), the adsorption time is 4h, and the adsorption buffer pH is 7.0 . The Km and Vmax of the free esterases were 35.66 mM and 4.46 mM/mg·min, respectively, The Km and Vmax of the immobilized PAE07 were 19.05 mM and 2.84 mM/mg·min. The SEM analysis showed that the immobilized esterase PAE07 had higher thermal stability, pH stability and substrate specifity than those from the free esterase. Under the optimal conditions,the reaction was carried out at 35°C and 200 rpm for resolution of 350 mM substrate for 14 hours, the conversion rate reached 48%, and the e.e.p was 99.5%.The repeatability of immobilized esterase PAE07 was evaluated by continuous catalytic resolution of (R, S)-DMPM. The results showed that after 15 times of repeated use, 86.2% of the relative enzyme activity was retained. These results proved that immobilized esterase PAE07 as a new catalyst had great potential for the application and industrial enzymatic resolution of (R, S)-DMPM to prepare (R)-metalaxyl.

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