Nanoclay Supporting Materials for Enzymes Immobilization: Kinetics Investigation of Free and Immobilized System

2013 ◽  
Vol 393 ◽  
pp. 115-120 ◽  
Author(s):  
Siti Noraida Abd Rahim ◽  
Alawi Sulaiman ◽  
Ku Halim Ku Hamid ◽  
Miradatul Najwa Mohd Rodhi ◽  
Musa Mohibah ◽  
...  
Keyword(s):  
Kinetic Parameters ◽  
Calcium Alginate ◽  
Alpha Amylase ◽  
Michaelis Constant ◽  
Cellulase Enzymes ◽  
Diffusional Limitation ◽  
Supporting Materials ◽  
Burk Plot

In this paper, the kinetic parameters of free and encapsulated enzymes in the calcium alginate-clay beads were determined using Lineweaver-Burk plot. The Michaelis constant, Kmof free alpha-amylase, glucoamylase and cellulase were 2.0831, 1.8326 and 7.8592 mg/mL, respectively, whereas for the encapsulated system, the Kmvalues were 3.1604, 2.1708 and 9.2791 mg/mL, respectively. The results showed encapsulation enzymes gave higher Kmvalue than the free enzymes. Comparatively the encapsulated alpha-amylase was 1.5 times higher and the glucoamylase and cellulase were 1.18 times higher. This suggests that the affinity of encapsulated enzymes for substrate was lower which might be due to the diffusional limitation of the substrate and enzymes. Amongst the three in both systems, glucoamylase was determined to have highest affinity followed by alpha-amylase and cellulase enzymes.

Kinetic parameters of hexose transport in hybrids between malignant and nonmalignant cells

1983 ◽  
Vol 62 (1) ◽  
pp. 49-80
Author(s):  
M.K. White ◽  
M.E. Bramwell ◽  
H. Harris
Keyword(s):  
Kinetic Parameters ◽  
Malignant Cell ◽  
Hexose Transport ◽  
Hybrid Cells ◽  
Michaelis Constant ◽  
Independent Measurement ◽  
The Difference ◽  
Hexose Uptake ◽  
Derivatives Of

Matched pairs of isogeneic hybrid cells, in which one member of the pair was malignant and the other not, were used to examine the linkage between malignancy and functional alterations in hexose transport. The kinetic parameters of uptake of 2-deoxy-D-glucose were measured in a range of such hybrids, both human and murine. Some other malignant cell lines were also examined and were compared with non-tumorigenic derivatives of tumour cells selected by exposure to the lectin, wheat-germ agglutinin. In every case, malignancy, as defined by the ability of cells to grow progressively in vivo, was found to be linked to a decrease in the Michaelis constant of hexose uptake. Independent measurement of the transport and phosphorylation reactions involved in hexose uptake revealed that this decrease was determined by the membrane transport system. The difference in Michaelis constant between malignant and non-malignant cells was observed with 3-O-methylglucose, a hexose that is transported into the cell but not further metabolized. The activity of hexokinase in cell homogenates was higher than the level that would be required to cope with transport and showed no correlation with tumorigenicity. Measurement of the uptake of D-glucose itself, by a rapid filtration centrifugation method, gave results similar to those obtained with 2-deoxy-D-glucose.

scholarly journals Kinetic properties of microtubule-activated 13 S and 21 S dynein ATPases251. Evidence for allosteric behaviour associated with the inner row and outer row dynein arms

1986 ◽  
Vol 83 (1) ◽  
pp. 251-267
Author(s):  
F.D. Warner ◽  
J.H. McIlvain
Keyword(s):  
Atpase Activity ◽  
Kinetic Parameters ◽  
Turnover Rate ◽  
Kinetic Properties ◽  
Significant Shift ◽  
Subunit Interactions ◽  
Michaelis Constant ◽  
Saturation Kinetics ◽  
Dynein Arms ◽  
Fixed Quantity

The 13 S and 21 S dynein ATPases from Tetrahymena cilia rebind to extracted doublet microtubules as inner row and outer row arms. Rebinding is accompanied by four- to ninefold activation of the ATPase activity. The soluble (microtubule-free) forms of the two dyneins exhibit simple saturation kinetics (h = 1.0) with Vmax much less than mumol Pi mg-1 min-1 and Km = 20–40 microM-ATP. Mixing a fixed quantity of free dynein with increasing concentrations of extracted doublets results in systematic increases in all three kinetic parameters for each dynein. At infinite concentrations of doublets and ATP, each enzyme undergoes a significant shift to sigmoid saturation kinetics (h = 2–3), Vmax increases to a turnover rate of about 90 mol ATP per mol Es-1 and the Michaelis constant increases to much greater than 100 microM-ATP. These data suggest that both enzymes are allosteric and can be interpreted in terms of positive cooperativity relative to a minimum of two or three interacting sites. It is less clear whether this cooperativity is related to subunit interactions within the 21 S or 13 S particles, or to subunit interactions between adjacent particles (arms) on the microtubule lattice.

A statistical comparison of parameter estimation for the Michaelis–Menten kinetics of human placental hexosaminidase

1985 ◽  
Vol 63 (3) ◽  
pp. 225-230 ◽  
Author(s):  
R. Tommasini ◽  
L. Endrenyi ◽  
P. A. Taylor ◽  
D. J. Mahuran ◽  
J. A. Lowden
Keyword(s):  
Least Squares ◽  
Kinetic Parameters ◽  
Least Squares Method ◽  
Nonlinear Least Squares ◽  
Linear Plot ◽  
Experimental Errors ◽  
Nonlinear Least Squares Method ◽  
Relative Errors ◽  
The One ◽  
Burk Plot

To enable the most effective method of kinetic discrimination between a group of isozymes such as those of human placental hexosaminidases (HEX), three methods estimating the parameters of the Michaelis–Menten equation were evaluated. Computer-simulated experiments were performed under various conditions. They indicated that, in the presence of constant absolute or relative errors, the method of unweighted nonlinear least squares yielded slightly more precise and accurate parameters than the method of the direct linear plot. Parameters calculated from the Lineweaver–Burk plot were very imprecise and inaccurate. The direct linear plot was comparatively resistant to outlier observations; however, only when outliers were substantial did the method become superior to nonlinear least squares. The calculation of a confidence limit is necessary for the evaluation of any resulting differences in the kinetic parameters for a set of isozymes. This can easily be calculated from either the Lineweaver–Burk plot or the nonlinear least-squares method. However, those calculated from the Lineweaver–Burk plot are biased, especially at higher levels of experimental errors. Therefore, the nonlinear least-squares method is the one most suited for the discrimination of a group of enzymes based on their kinetic parameters.

scholarly journals Effect of Agricultural Exploitation on the Activity of Alkaline Phosphatase and Its Kinetic Properties in Some Soils

2019 ◽  
Vol 9 (1) ◽  
pp. 120-135
Author(s):  
Luma Salih Jabbar Al-Taweel ◽  
Gaith Abedulkadhim Alwan Al- Jubouri
Keyword(s):  
Alkaline Phosphatase ◽  
Kinetic Parameters ◽  
Maximum Velocity ◽  
Biological Properties ◽  
Kinetic Properties ◽  
Field Soil ◽  
Michaelis Constant ◽  
Orchard Soil ◽  
Controlled Substance

In order to study the role of agricultural exploitation in the activity of alkaline phosphatase in the province of Diwaniyah, six sites that differ in some of their chemical, physical and biological properties were selected (Diwaniyah, Sunniya, Shamiya, Daghara, Afak and Al Budair). Three types of soils were chosen in each location, namely, orchard soil, field soil and jungle soil. The kinetic parameters of the enzymes maximum velocity (Vmax) and Michaelis constant (Km) were estimated in all study soils using increasing concentrations of the controlled substance. The results present that the highest efficacy of this enzyme is in the orchard soil of all sites except the location of the center Diwaniyah and Shamia. The average efficacy values ranged between (208.11 - 234.95) μg P-Nitro phenol. g-1 soil. 1 hour-1. The highest value of maximum velocity (Vmax) recorded at the field soil of Al-Shamia site (108.57) μg P-Nitro phenol. g-1 soil. 1 hour-1. The lowest value recorded at the soil of a jungle field at the Sunniya location (49.62) μg P-nitro phenol. g-1 soil. 1 hour-1. While the orchard soil of Al-Budair had the highest value of the Michaelis constant (Km) of (85.90) mM, the orchard soil of the Sunniya location had the lowest value (24.34) mM.

scholarly journals Inhibition Effect of Ca2+ Ions on Sucrose Hydrolysis Using Invertase

2019 ◽  
Vol 14 (3) ◽  
pp. 646 ◽  
Author(s):  
Hargono Hargono ◽  
Bakti Jos ◽  
Abdullah Abdullah ◽  
Teguh Riyanto
Keyword(s):  
Kinetic Parameters ◽  
Competitive Inhibition ◽  
Substrate Inhibition ◽  
Competitive Inhibitor ◽  
Inhibition Mechanism ◽  
Fermentable Sugar ◽  
Sucrose Hydrolysis ◽  
Substrate Concentrations ◽  
High Sucrose ◽  
Burk Plot

Fermentable sugar for bioethanol production can be produced from molasses due to its high sucrose content but Ca2+ ions found in the molasses may affect the hydrolysis. Therefore, this paper was focused to study the effect of Ca2+ ions as CaO on sucrose hydrolysis using invertase and to obtain the kinetic parameters. The kinetic parameters (KM and Vmax) were obtained using a Lineweaver-Burk plot. The value of KM and Vmax parameters were 36.181 g/L and 21.322 g/L.h, respectively. The Ca2+ ions act as competitive inhibitor in sucrose hydrolysis using invertase. Therefore, the inhibition mechanism was followed the competitive inhibition mechanism. The value of inhibition constant was 0.833 g/g. These parameters were obtained from the non-substrate inhibition process because this study used the low substrate concentrations which means the fermentable sugar production was low. Hence, there were still more challenges to studying the simultaneous effect of substrate and Ca2+ on sucrose hydrolysis to produce high fermentable sugar. Copyright © 2019 BCREC Group. All rights reserved 

scholarly journals Amylase Production by Aspergillus niger immobilized in Microporous Calcium Alginate Gel Beads

2021 ◽  
Vol 26 (4) ◽  
pp. 2825-2833
Author(s):  
UCHENNA OYEAGU ◽  
CHARLES NWUCHE ◽  
CHRISTIAN OGBONNA ◽  
JAMES OGBONNA
Keyword(s):  
Aspergillus Niger ◽  
Calcium Chloride ◽  
Calcium Alginate ◽  
Chloride Concentration ◽  
Alpha Amylase ◽  
Alginate Gel ◽  
Gel Beads ◽  
Amylase Production ◽  
Calcium Alginate Gel ◽  
Bead Diameter

Microporous calcium alginate gel beads were investigated as potential solutions to mass transfer limitations in immobilized cultures. The beads were prepared by gelling mixtures of sodium alginate and fillers (starch or granulated sugars) in calcium chloride solution. The resulting beads were cured in the same solution, during which the fillers leached out of the beads thereby creating micro-pores in the beads (microporous beads). The effectiveness of the microporous beads in improving amylase production by Aspergillus niger LC 269109 was investigated. Spores of A. niger were immobilized in the microporous beads and used for batch alpha amylase and gluco amylase production. Amylase production by the A. niger immobilized in the microporous beads were significantly higher (p<0.01) than the values obtained with the conventional calcium alginate gel beads. Under all the conditions investigated, gluco-amylase activities were significantly (p<0.01) higher than the alpha-amylase activities. Under the optimum conditions of inoculum concentration (1.0 × 105 spores/ml), pH (6), temperature (35°C), bead diameter (3 mm) and calcium chloride concentration (1.5%), the gluco-amylase and alpha amylase activities were 11.98 U/ml and 6.7 U/ml respectively, which were significantly higher (p<0.05) than the 7.8 U/ml and 3.2 U/ml obtained with the conventional gel beads.

scholarly journals Optimization and Immobilization of alpha-amylase from Bacillus subtilis in calcium alginate and calcium alginate – cellulosic residue beads

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Abdallah Herizi ◽  
Souilah Rachid ◽  
Djabali Djaffar ◽  
Nadjemi Boubekeur
Keyword(s):  
Bacillus Subtilis ◽  
Calcium Alginate ◽  
Immobilized Enzymes ◽  
Alginate Beads ◽  
Alpha Amylase ◽  
Inhibitory Effects ◽  
Calcium Alginate Beads ◽  
Factorial Design Of Experiments ◽  
Full Factorial ◽  
Hydrolysis Of

In this study, Alpha amylase from Bacillus subtilis was immobilized by entrapment in Calcium Alginate beads (CA). To improve the properties of these beads, alginate was blended with Cellulosic Residue (CR) obtained from sorghumstarch extraction. The conditions of entrapment were optimized for a maximum immobilization yield (Y%) by mathematical statistics, where the 23-full factorial design of experiments was used. The properties of calcium alginate beads were improved by comparing the activity of immobilized enzymes in the hydrolysis of starch. The activity of the immobilized enzyme by Calcium Alginate /Cellulosic Residue (CA/CR) was found to be higher than the Calcium Alginate method. Zn2+ and Cu2+ have inhibitory effects on both immobilized enzymes. The Bacillus subtilis immobilized in alginate can be reused for 7 cycles with 12.7 μmol of reduced sugars and 6 cycles for the entrapped enzyme in CA/CR with 30 μmol of reduced sugars.

scholarly journals Alpha Amylase Inhibitory Potential and Mode of Inhibition of Oils from Allium sativum (Garlic) and Allium cepa (Onion)

2020 ◽  
Vol 13 ◽  
pp. 117955142096310
Author(s):  
Maryam Usman Ahmed ◽  
Adamu Ibrahim ◽  
Noseh Janyo Dahiru ◽  
Hauwa’u Shuaibu Mohammed
Keyword(s):  
Diabetes Mellitus ◽  
Allium Cepa ◽  
Type Ii Diabetes ◽  
Allium Sativum ◽  
Type Ii Diabetes Mellitus ◽  
Alpha Amylase ◽  
Type Ii ◽  
Percent Inhibition ◽  
Inhibitory Potential ◽  
Burk Plot

Background: Alpha amylase inhibitors are used in the treatment of type II diabetes mellitus. Allium sativum and Allium cepa, widely consumed as spices have several medicinal uses which include their traditional use in the management of diabetes. This study was conducted to investigate the alpha amylase inhibitory potential and mode of inhibition of A. sativum and A. cepa oils. Method: Oil was extracted from dried bulb of A. sativum and A. cepa by Soxhlet extraction. The α-amylase inhibitory potential of the 2 oils were evaluated. The mode of inhibition of the oils were determined from the lineweaver-burk plot and the kinetic parameters obtained from the lineweaver – burk plot. Result: A. sativum oil had 58.13 ± 1.09 and 69.8 ± 1.11 percent inhibition at 5.0 and 7.0% concentrations respectively while A. cepa oil had 55.45 ± 1.35, 59.73 ± 1.11 and 65.21 ± 1.11 percent inhibition at 5.0, 7.5 and 10% concentrations respectively. The IC50 values for A. sativum oil, A. cepa oil and acarbose were 3.0 ± 0.02%, 4.4 ± 0.03% and 14.1 ± 0.09% respectively. The lineweaver – burk plot showed that the Vmax of the 2 oils did not change when compared with that of the no inhibitor (no oil) but the Km increased. Conclusion: These findings indicate that A. sativum and A. cepa oils are competitive inhibitors of α- amylase and can both be used in the treatment of type II diabetes mellitus. A. sativum oil is a better inhibitor than A. cepa oil.

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