Spectrophotometric determination of lanthanides with calmagite

Brittain, Harry G.

doi:10.1016/s0003-2670(01)85029-7

Cited by 15 publications

(4 citation statements)

References 20 publications

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“…Methods. The concentrations of calcium chloride in stock solutions were measured as described by Brittain (1979). Steady-state ATP hydrolysis was measured spectrophotometrically by coupling the formation of ADP to oxidation of NADH with pyruvate kinase and lactate dehydrogenase (Rossi et al, 1979).…”

Section: Scheme Imentioning

confidence: 99%

The binding of ATP and magnesium to the calcium adenosinetriphosphatase of sarcoplasmic reticulum follows a random mechanism

Reinstein

Jencks²

1993

Biochemistry

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The enzyme form of the calcium adenosinetriphosphatase of sarcoplasmic reticulum (CaATPase) that is stable in the presence of calcium, cE.Ca2, has a binding site for the catalytic Mg2+ ion with a dissociation constant of 0.94 +/- 0.15 mM at 25 degrees C, pH 7.0, and 100 mM KCl. This is approximately 10 times smaller than that reported for the free enzyme, E, (8.8 mM) under similar conditions [Punzengruber, C., Prager, R., Kolassa, N., Winkler, F., & Suko, J. (1978) Eur. J. Biochem. 92, 349-359]. This difference shows that the sites for the catalytic and the transported ions interact in the absence of ATP. The addition of ATP and EDTA to enzyme that had been incubated with Ca2+ and Mg2+ resulted in the formation of 61% phosphoenzyme. The addition of unlabeled ATP and Mg2+ to enzyme that had been incubated with 3.5 microM free Ca2+ and labeled ATP gave 39% labeled phosphoenzyme. This shows that the binding of ATP and Mg2+ to cE.Ca2 follows a random mechanism. The rate constants for dissociation of ATP and Mg2+ from cE.Ca2.ATP.Mg are different: kdiss(ATP) = 120 s-1 and kdiss(Mg2+) = 60 s-1. This shows that Mg2+ and ATP can bind and dissociate independently; they do not have to associate or dissociate from cE as a Mg.ATP complex. Calcium-free enzyme binds metal-free ATP at the active site with a dissociation constant of 44 +/- 4 microM, kdiss = 130 +/- 7 s-1, and a calculated association rate constant of 3 x 10(6) M-1 s-1. Calcium-free enzyme that was incubated with [gamma-32P]ATP gave 38% labeled phosphoenzyme when chased with unlabeled ATP, Mg2+, and Ca2+. An increase of the Mg2+ concentration did not increase the amount of E32P formed. This shows that the binding of Mg2+ and ATP to free E also follows a random mechanism. The Mg2+ ion is not buried under ATP, and ATP is not under a Mg2+ ion. Incubation of free E with Mg2+ and ATP causes a conformational change that activates the enzyme for phosphorylation and decreases the rate constant for the dissociation of ATP from kdiss = 120 s-1 to kdiss = 47 s-1.

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Section: Scheme Imentioning

confidence: 99%

The binding of ATP and magnesium to the calcium adenosinetriphosphatase of sarcoplasmic reticulum follows a random mechanism

Reinstein

Jencks²

1993

Biochemistry

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“…The limit of detection is lower than many of the reagents previously reported and the useful range of the spectrophotometric measurement (0.1-4 ppm) can favorably be compared with those of laser emission spectrography (10-60 ppm) (28), X-ray fluorescence (0.2-2 ppm) (29), and atomic absorption spectrometry (0.1-10 ppm) (30). Moreover, alkaline earth, zinc, aluminum, and other ions which commonly interfere with many of the available spectrophotometric procedures (3,6,(12)(13)(14)16,17) have no effect. Interferences by some other metals can be tolerated by precipitating the lanthanides or extracting the interfering ions.…”

Section: Methodsmentioning

confidence: 99%

“…The worldwide interest in lanthanides as fission products and their uses for production of some modified alloys, ceramics, optical crystals, and semiconductors have necessitated the development of suitable methods for their accurate determination. Among the various instrumental methods, spectrophotometry has shown to be a simple and reliable technique applicable for quantitation of a wide range of concentrations (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17). However, many of these methods are not sensitive enough to permit accurate determination of trace levels of these metals, involve a time-consuming extraction step, develop unstable colors, and require a long time for full color development (6,8,10,13,16).…”

mentioning

confidence: 99%

“…However, many of these methods are not sensitive enough to permit accurate determination of trace levels of these metals, involve a time-consuming extraction step, develop unstable colors, and require a long time for full color development (6,8,10,13,16). On the other hand, metals frequently associated or naturally occurring as contaminants with lanthanides (e.g., alkaline earths, zinc, and aluminum) seriously interfere with most of these reagents (3,6,12,14,16,17).…”

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confidence: 99%

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Spectrophotometric, potentiometric, and gravimetric determination of lanthanides with peri-dihydroxynaphthindenone

Hassan¹,

Mahmoud²

1982

Anal. Chem.

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Sensltlve and reasonably selectlve methods are descrlbed for the spectrophotometrlc, potentlometrlc, and gravlmetrlc determfnatlon of lanthanldes using perl-dlhydroxynaphthlndenone as a novel chromogenlc and preclpltatlng reagent. The reagent forms a stable 1:2 (metakreagent) type of complex wlth light lanthanides at pH 2-7 In 1:l ethanol-water mlxture. Low metal concentratlons ( < I O pg/mL) develop colored specles ( A, 580-590 nm, emax (4-6) X lo4 L mol-' cm-') whlch obey Beer's law. Quantltatlve preclpltatlon of the complexes from metal solutlons of concentratlons > 100 pg/mL permlts both gravlmetrlc quantltatlon by lgnltlng the preclpltates to the metal oxides and potentlometrlc tltratlon of the excess reagent. Results wlth an average recovery of 98% (standard devlatlon 0.7%) are obtainable for 0.1 kg to 200 mg of all light lanthanldes. Many forelgn Ions naturally occurrlng or frequently assoclated wlth lanthanldes do not Interfere or can be tolerated.

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Analytical Aspects of Compounds Containing the Azo, Azoxy and Hydrazino Functional Groups

Zabicky

Grinberg

2009

Patai's Chemistry of Functional Groups

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Introduction Analysis of Azo Compounds Analysis of Azoxy Compounds Analysis of Hydrazino Compounds Azo Compounds as Analytical Tools Hydrazines as Analytical Tools Analytical Properties of Analytical Reagents

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Spectrophotometric determination of lanthanides with calmagite

Cited by 15 publications

References 20 publications

The binding of ATP and magnesium to the calcium adenosinetriphosphatase of sarcoplasmic reticulum follows a random mechanism

The binding of ATP and magnesium to the calcium adenosinetriphosphatase of sarcoplasmic reticulum follows a random mechanism

Spectrophotometric, potentiometric, and gravimetric determination of lanthanides with peri-dihydroxynaphthindenone

Analytical Aspects of Compounds Containing the Azo, Azoxy and Hydrazino Functional Groups

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