Effect of Calcium on the Reversible Thermal Inactivation of Lignin Peroxidase

Nie, Guojun; Aust, Steven D.

doi:10.1006/abbi.1996.9770

Cited by 42 publications

(33 citation statements)

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“…Our studies complement the thermal inactivation studies on LiP H8 [24,25] and manganese peroxidase [26] when only the distal and adventitious calcium ions were lost (the proximal Ca# + being retained) and show that thermal and alkali treatments yield structurally different inactive species. Recent studies with barley peroxidase have suggested that the activity of plant peroxidases may be reversibly controlled by pH and Ca# + -induced conformation changes [27].…”

Section: Introductionsupporting

confidence: 63%

“…By contrast, the proximal calcium predicted to be more tightly bound is inaccessible to bulk solvent and has no bound water. During thermal inactivation of LiP [24,25] and manganese peroxidase [26,41] only the more weakly-bound distal Ca# + is thought to dissociate. The LiP H8 preparation used by Nie and Aust [24] contained 5 g-atom of Ca# + per mol, of which four were lost on thermal inactivation at 50 mC, the authors proposing that their enzyme contained four weakly-bound, adventitious calcium ions that are not detectable in the X-ray crystal structure.…”

Section: Implications For Ca 2 + Dissociation From Alkali-treated Lip H2mentioning

confidence: 99%

“…One of the key factors in evaluating the technological feasibility of these environmentally acceptable bio-bleaching systems is the stability of the peroxidases, particularly at high pH. Unfortunately, LiP has an extremely narrow pH optimum (pH 2.7-3.0) with respect to the majority of its substrates, and rapidly converts into a denatured species at pH 7.5 [23], particularly at elevated temperatures [24,25].…”

Section: Introductionmentioning

confidence: 99%

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Reversible alkaline inactivation of lignin peroxidase involves the release of both the distal and proximal site calcium ions and bishistidine co-ordination of the haem

George

Kvaratskhelia

Dilworth

et al. 1999

Biochemical Journal

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Phanerochaete chrysosporium lignin peroxidase isoenzyme H2 (LiP H2) exhibits a transition to a stable, inactive form at pH 9.0 with concomitant spectroscopic changes. The So$ ret peak intensity decreases some 55 % with a red shift from 408 to 412 nm ; the bands at 502 nm and 638 nm disappear and the peak at 536 nm increases. The EPR spectrum changes from a signal typical of high spin ferric haem to an exclusively low spin spectrum with g l 2.92, 2.27, 1.50. These data indicate that the active pentacoordinated haem is converted into a hexaco-ordinated species at alkaline pH. Room temperature near-IR MCD data coupled with the EPR spectrum allow us to assign the haem co-ordination of alkali-inactivated enzyme as bishistidine. Re-acidification of the alkali-inactivated enzyme to pH 6 induces further spectroscopic changes and generates an irreversibly inactivated species. By contrast, a pH shift from 9.0 to 6.0 with simultaneous addition of 50 mM CaCl # results in the recovery of the initial

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Section: Introductionsupporting

confidence: 63%

Section: Implications For Ca 2 + Dissociation From Alkali-treated Lip H2mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Reversible alkaline inactivation of lignin peroxidase involves the release of both the distal and proximal site calcium ions and bishistidine co-ordination of the haem

George

Kvaratskhelia

Dilworth

et al. 1999

Biochemical Journal

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“…The peroxidase activity in roots of tomato plants treated with Ca(NO 3 ) 2 has been reported to be significantly higher than in roots of untreated plants [15]. Similarly, the peroxidase activity in the roots of transgenic tobacco plants was found to increase with an increasing concentration of 3 …”

Section: Calcium Salts Enhance Activity and Azo Dye Decolourisation Cmentioning

confidence: 79%

“…Calcium acts to maintain the functional conformation of some proteins like Horseradish Peroxidase [1]. Studies with lignin peroxidase have shown that calcium ions are important for the heme environment of the enzyme and thereby affect its activity [3,4]. The role of calcium in the growth of plants and in the maintenance of their health has been studied extensively.…”

Section: Introductionmentioning

confidence: 99%

Calcium Salts Enhance Activity and Azo Dye Decolourisation Capacity of Crude Peroxidase from <i>Armoracia rusticana</i>

Ambatkar¹,

Mukundan²

2014

AJPS

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Armoracia rusticana is the commercial source of the enzyme Horseradish Peroxidase (HRP). Calcium ions play an important role in the functional conformation of HRP. The present study assesses the effect of three calcium salts viz., calcium chloride (CaCl 2 ), calcium nitrate [Ca(NO 3 ) 2 ] and calcium sulphate (CaSO 4 ) on the guaiacol activity of crude peroxidase extracted from the shoots and roots of in vitro grown plantlets of A. rusticana and their growth medium. The highest activity was observed in the shoot extracts of 25 mM CaCl 2 treated plantlets (1.92 U/mL) and the root extracts of 25 mM Ca(NO 3 ) 2 supplemented plantlets (2.84 U/mL). The crude peroxidase activity of the medium containing 25 mM CaCl 2 supplement was highest (0.13 U/mL). The capacity of the shoot and root extracts to decolourise a 10 ppm solution of methyl orange over 48 hours, was also tested. The decolourisation capacity was highest in the shoot extracts from CaCl 2 treated plantlets (49.32%) and root extracts from Ca(NO 3 ) 2 treated plantlets (29.72%) respectively. Hence, the addition of calcium salts to growth medium enhances both peroxidase activity and decolourisation capacity of crude extracts of A. rusticana plantlets. These findings are of significance in enzymatic treatment for decolourisation of effluents containing dyestuffs.

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Biochemical analysis and kinetic modeling of the thermal inactivation of MBP‐fused heparinase I: Implications for a comprehensive thermostabilization strategy

Chen

et al. 2011

Biotech & Bioengineering

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Enzymatic degradation of heparin by heparin lyases has not only largely facilitated heparin structural analysis and contamination detection, but also showed great potential to be a green and cost-effective way to produce low molecular weight heparin (LMWH). However, the commercial use of heparinase I (HepI), one of the most studied heparin lyases, has been largely hampered by its low productivity and extremely poor thermostability. Here we report the thermal inactivation mechanism and strategic thermal stabilization of maltose-binding protein (MBP)-HepI, a fusion HepI produced in E. coli with high yield, solubility and activity. Biochemical studies demonstrated that the thermal inactivation of MBP-HepI involves an unfolding step that is temperature-dependently reversible, followed by an irreversible dimerization step induced by intermolecular disulfide bonds. A good consistency between the kinetic modeling and experimental data of the inactivation was obtained within a wide range of temperature and enzyme concentration, confirming the adequacy of the proposed inactivation model. Based on the inactivation mechanism, a comprehensive strategy was proposed for the thermal stabilization of MBP-HepI, in which Ca(2+) and Tween 80 were used to inhibit unfolding while site mutation at Cys297 and DTT were employed to suppress dimerization. The engineered enzyme exhibits remarkably improved storage and operational thermostability, for example, 16-fold increase in half-life at its optimum temperature of 30 °C and 8-fold increase in remaining activity of 95% after 1-week storage at 4 °C, and therefore shows great potential as a commercial biocatalyst for heparin degradation in the pharmaceutical industry.

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Effect of Calcium on the Reversible Thermal Inactivation of Lignin Peroxidase

Cited by 42 publications

References 0 publications

Reversible alkaline inactivation of lignin peroxidase involves the release of both the distal and proximal site calcium ions and bishistidine co-ordination of the haem

Reversible alkaline inactivation of lignin peroxidase involves the release of both the distal and proximal site calcium ions and bishistidine co-ordination of the haem

Calcium Salts Enhance Activity and Azo Dye Decolourisation Capacity of Crude Peroxidase from <i>Armoracia rusticana</i>

Biochemical analysis and kinetic modeling of the thermal inactivation of MBP‐fused heparinase I: Implications for a comprehensive thermostabilization strategy

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Effect of Calcium on the Reversible Thermal Inactivation of Lignin Peroxidase

Cited by 42 publications

References 0 publications

Reversible alkaline inactivation of lignin peroxidase involves the release of both the distal and proximal site calcium ions and bishistidine co-ordination of the haem

Reversible alkaline inactivation of lignin peroxidase involves the release of both the distal and proximal site calcium ions and bishistidine co-ordination of the haem

Calcium Salts Enhance Activity and Azo Dye Decolourisation Capacity of Crude Peroxidase from &lt;i&gt;Armoracia rusticana&lt;/i&gt;

Biochemical analysis and kinetic modeling of the thermal inactivation of MBP‐fused heparinase I: Implications for a comprehensive thermostabilization strategy

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Calcium Salts Enhance Activity and Azo Dye Decolourisation Capacity of Crude Peroxidase from <i>Armoracia rusticana</i>