Browsing by Author "Rajesh K. Pandey"

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Enzymatic detection of heavy metal ions in aqueous solution from vegetable wastes by immobilizing pumpkin (Cucumis melo) urease in calcium alginate beads
(2008) Om Prakash; Mahe Talat; S.H. Hasan; Rajesh K. Pandey
Enzyme urease is extracted from the discarded seeds of pumpkin. Urease was purified to apparent homogeneity (5.2 fold) by heat treatment at 48 ± 1°C and gel filtration through Sephadex G-200. Effect of model metal ions on the activity of the homogeneous enzyme preparation (sp. activity 353 U/mg protein, A280/A260 = 1.12) of soluble as well as immobilized enzyme was investigated. The soluble and immobilized urease has been used for the quantitative estimation of general water pollution with heavy metal ions like Hg2+, Cu2+, Cd2+, and Co2+. The measurements of the urease residual activity have been carried out in tris-acetate buffer after pre-incubation of model metal salt. The inhibition was found to be biphasic with an initial rapid loss of activity and remainder in slow phase of 10-15 min. The immobilization was done in 3.5% alginate beads leading to 86% of entrapment. There was no leaching of the enzyme over a period of 15 days at 4°C. The beads were fairly stable up to 50°C and exhibited activity even at -10°C. The inhibition by these ions was non-competitive and irreversible, hence could not be restored by dialysis. Based on the values of inhibition constant Ki the heavy-metal ions were found to inhibit urease in the following order Hg2+ > Cu2+ > Cd2+ > Co2+. © KSBB.
Enzymatic detection of mercuric ions in ground-water from vegetable wastes by immobilizing pumpkin (Cucumis melo) urease in calcium alginate beads
(2008) Om Prakash; Mahe Talat; Syed Hadi Hasan; Rajesh K. Pandey
Present report describes a quick and simple test based on enzyme inhibition for the detection of mercury in aqueous medium by urease immobilized in alginate beads. Urease was extracted from the discarded seeds of pumpkin (Cucumis melo) and was purified to apparent homogeneity (5.2-fold) by heat treatment at 48 ± 0.1 °C and gel filtration through Sephadex G-200. The homogeneous enzyme preparation (Sp activity 353 U/mg protein, A280/A260 = 1.12) was immobilized in 3.5% alginate leading to 86% immobilization. Effect of mercuric ion on the activity of soluble as well as immobilized enzyme was investigated. Hg2+ exhibited a concentration-dependent inhibition both in the presence and absence of the substrate. The alginate immobilized enzyme showed less inhibition. There was no leaching of the enzyme over a period of 15 days at 4 °C. The inhibition was non-competitive and the Ki was found to be 1.26 × 10-1 μM. Time-dependent interaction of urease with Hg2+ exhibited a biphasic inhibition behavior in which approximately half of the initial activity was lost rapidly (within 10 min) and reminder in a slow phase. Binding of Hg2+ with the enzyme was largely irreversible, as the activity could not be restored by dialysis. The significance of the observations is discussed. © 2007 Elsevier Ltd. All rights reserved.
Factorial design for the optimization of enzymatic detection of cadmium in aqueous solution using immobilized urease from vegetable waste
(2008) Om Prakash; Mahe Talat; S.H. Hasan; Rajesh K. Pandey
Free as well as alginate immobilized urease was utilized for detection and quantitation of cadmium (Cd2+) in aqueous samples. Urease from the seeds of pumpkin (Cucumis melo), being a vegetable waste, was extracted and purified to apparent homogeneity (Sp. Activity 353 U/mg protein; A280/A260 = 1.12) by heat treatment at 48 ± 0.1 °C and gel filtration through Sephadex G-200. The homogeneous enzyme preparation was immobilized in 3.5% alginate leading to 86% immobilization and no leaching of the enzyme was found over a period of 15 days at 4 °C. Urease catalyzed urea hydrolysis by both soluble and immobilized enzyme revealed a clear dependence on the concentration of Cd2+. The inhibition caused by Cd2+ was non-competitive (Ki = 1.41 × 10-5 M). The time dependent inhibition both in the presence and in absence of Cd2+ ion revealed a biphasic inhibition in the activity. A Response Surface Methodology (RSM) for the parametric optimization of this process was performed using two-level-two-full factorial (22), central composite design (CCD). The regression coefficient, regression equation and analysis of variance (ANOVA) was obtained using MINITAB® 15 software. The predicted values thus obtained were closed to the experimental value indicating suitability of the model. In addition to this 3D response surface plot and isoresponse contour plot were helpful to predict the results by performing only limited set of experiments. © 2008 Elsevier Ltd. All rights reserved.
Fluoride quantitation in aqueous solution by agarose immobilized pumpkin urease
(2011) Om Prakash; Rajesh K. Pandey; Mahe Talat; Nivedita Jaiswal
Soluble as well as agarose immobilized pumpkin urease was utilized for easy and rapid detection and quantitation of fluoride in aqueous solution. Pumpkin urease was immobilized in 1.5 % agarose leading to 74.2 % immobilization. Inhibition by both soluble and agarose immobilized enzyme revealed a clear dependence on concentration and time. In order to inhibit the activity completely in soluble enzyme, 45 mM fluoride was required while agarose immobilized enzyme required almost double the concentration of the inhibitor i.e., 80 mM. The inhibition caused by fluoride was noncompetitive with K i value of 3.9 and 2.3 mM. The significance of the observations is discussed. © 2011 Bentham Science Publishers.
Legendre collocation method for new generalized fractional advection-diffusion equation
(Taylor and Francis Ltd., 2024) Sandeep Kumar; Kamlesh Kumar; Rajesh K. Pandey; Yufeng Xu
In this paper, the numerical method for solving a class of generalized fractional advection-diffusion equation (GFADE) is considered. The fractional derivative involving scale and weight factors is imposed for the temporal derivative and is analogous to the Caputo fractional derivative following an integration-after-differentiation composition. It covers many popular fractional derivatives by fixing different weights (Formula presented.) and scale functions (Formula presented.) inside. The numerical solution of such GFADE is derived via a collocation method, where conventional Legendre polynomials are implemented. Convergence and error analysis of polynomial expansions are studied theoretically. Numerical examples are considered with different boundary conditions to confirm the theoretical findings. By comparing the above examples with those from existing literature, we find that our proposed numerical method is simple, stable and easy to implement. © 2024 Informa UK Limited, trading as Taylor & Francis Group.