Browsing by Author "Asha Anand"

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A molecular description of acid phosphatase
(2012) Asha Anand; Pramod Kumar Srivastava
Acid phosphatase is ubiquitous in distribution in various organisms. Although it catalyzes simple hydrolytic reactions, it is considered as an interesting enzyme in biological systems due to its involvement in different physiological activities. However, earlier reviews on acid phosphatase reveal some fragmentary information and do not give a holistic view on this enzyme. So, the present review summarizes studies on biochemical properties, structure, catalytic mechanism, and applications of acid phosphatase. Recent advancement of acid phosphatase in agricultural and clinical fields is emphasized where it is presented as potent agent for sustainable agricultural practices and diagnostic marker in bone metabolic disorders. Also, its significance in prostate cancer therapies as a therapeutic target has been discussed. At the end, current studies and prospects of immobilized acid phosphatase are included. © Springer Science+Business Media, LLC 2012.
Immobilization of acid phosphatase from Vigna aconitifolia seeds on chitosan beads and its characterization
(Elsevier B.V., 2014) Pramod Kumar Srivastava; Asha Anand
Acid phosphatase isolated from Vigna aconitifolia seeds was immobilized onto glutaraldehyde activated chitosan beads by crosslinking method. Chitosan beads activated with 2% of glutaraldehyde have demonstrated maximum immobilization yield (~83%). The immobilized enzyme showed optimum activity at pH 7.0, while soluble form was maximally active in acidic range (pH 5.0). With respect to free form, immobilized acid phosphatase showed better activity in alkaline range. On the other side, immobilization does not affect the optimum temperature range i.e., both, soluble and immobilized acid phosphatase exhibited maximum activity at 60°C. The Km and Vmax values for the immobilized enzyme were calculated to be 0.37mM and 13.5U/mg. The immobilization on chitosan beads enhanced the shelf life of acid phosphatase. The immobilized enzyme retained its more than 50% hydrolytic activity for approximately two months. The immobilized acid phosphatase was reusable for more than 40 cycles of reaction. © 2013 Elsevier B.V.
Isolation and enzymatic properties of a nonspecific acid phosphatase from Vigna aconitifolia seeds
(Wiley-Blackwell Publishing Ltd, 2014) Asha Anand; Pramod Kumar Srivastava
Acid phosphatase (EC 3.1.3.2) from Vigna aconitifolia seeds was purified to apparent homogeneity by using ammonium sulfate fractionation and cation-exchange chromatography [carboxymethyl (CM) cellulose]. The enzyme was 228-fold purified with 14.6% recovery. Analytical gel filtration chromatography on Sephadex G-200 column showed that Mr of native enzyme was 58 kDa and denaturing PAGE demonstrated that it was made up of two subunits of 24 and 27 kDa. The enzyme showed its optimum activity at pH 5.0 and 60°C. It exhibited broad substrate specificity and showed a higher specificity constant for para-nitrophenyl phosphate, Na β-naphthyl phosphate, and adenosine monophosphate (AMP). Cu2+, Mo6+, Fe3+, phosphate, and fluoride ions were reported as strong inhibitors for the enzyme. Active site study for the enzyme demonstrated that tryptophan and aspartic acid may be important for the catalysis. © 2013 International Union of Biochemistry and Molecular Biology, Inc.
Role of metabolites and significance of SH groups in the action of NADP+-linked isocitrate dehydrogenase of urdbean seeds (Phaseolus mungo L.)
(2011) Pramod Kumar Srivastava; Govind Kant Srivastava; Indra Mani; Sharawan Yadav; Asha Anand
NADP+-linked-isocitrate dehydrogenase (EC 1.1.1.42) is a key enzyme of the Tricarboxylic Acid Cycle (TCA) and has been purified from urdbean seeds and it is inhibited by ATP in a competitive manner having inhibitor constant (Ki 1.32 mM. Phosphoenol-pyruvate, an energy rich compound plays an important role in the regulation of this enzyme and this metabolite inhibited the enzyme activity of NADP+-linked-isocitrate dehydrogenase of urdbean with inhibitor constant (Ki 2.66 mM in a competitive manner. The mode of inhibition by various metabolites of Krebs cycle has been carried out and found that oxaloacetate and succinate inhibit ICDH urdbean enzyme in a competitive manner with respect to isocitrate and their Ki values are found to be 7.27 and 10.67 mM, respectively. Citrate inhibits the urdbean ICDH enzyme non competitively with Ki revalue equal to 3.33 mM. The SH groups play a important role in the activity of NADP+-linked-isocitrate dehydrogenase and blocking of this group with SH-reagents, leads to inactivation of urdbean ICDH enzyme. With excess iodoacetamide (1.00 mM) and N-ethylmaleimide (4.0 mM) inhibition of this enzyme follows first order kinetics, suggesting that there are four reactive SH groups per mole of enzyme which are equally reactive and there is no site- site interaction among the tetrameric isoicitrate dehydrogenase of urdbean. © 2011 Academic Journals Inc.
The inhibitory effect of metals and other ions on acid phosphatase activity from vigna aconitifolia seeds
(Taylor and Francis Inc., 2015) Pramod Kumar Srivastava; Asha Anand
Sensitivity of acid phosphatase from Vigna aconitifolia seeds to metal ions, fluoride, and phosphate was examined. All the effectors had different degree of inhibitory effect on the enzyme. Among metal ions, molybdate and ferric ion were observed to be most potent inhibitors and both exhibited mixed type of inhibition. Acid phosphatase activity was inhibited by Cu2+ in a noncompetitive manner. Zn and Mn showed mild inhibition on the enzyme activity. Inhibition kinetics analysis explored molybdate as a potent inhibitor for acid phosphatase in comparison with other effectors used in this study. Fluoride was the next most strong inhibitor for the enzyme activity, and caused a mixed type of inhibition. Phosphate inhibited the enzyme competitively, which demonstrates that inhibition due to phosphate is one of the regulatory factors for enzyme activity. © 2015 Taylor and Francis Group, LLC.