On the rapid, monophasic reaction of the rabbit liver metallothionein .alpha.-domain with 5,5'-dithiobis (2-nitrobenzoic acid) (DTNB)

Savaş, Murat; Petering, David H.; Shaw, C. Frank

doi:10.1021/ic00003a049

Cited by 31 publications

(47 citation statements)

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“…The reaction of each zinc cluster with excess DTNB is biphasic, which contrasts with an earlier report of a monophasic reaction between the cadmium ␣-cluster and DTNB (17). The difference observed could be caused by the different ranges of DTNB concentrations used in these studies, because we also observe a monophasic process for the ␣-cluster at a concentration of 1.5 mM DTNB.…”

Section: Discussioncontrasting

confidence: 99%

“…The ␣-and ␤-clusters were dissolved in 1 ml of 100 mM sodium perchlorate and the pH was changed with 5-500 mM perchloric acid and measured with a micro-NMR pH electrode (Orion, Boston) at 25°C. (17). In the first instance, the reactivity of the clusters (10 M) with DTNB (4 M) was measured in 0.2 M Tris⅐HCl, pH 7.4 (12), whereas in the second instance, clusters (5 M) and DTNB (from 0.25 to 1.5 mM) were reacted in 5 mM Tris⅐HCl, pH 7.4, containing 0.1 M KCl (17).…”

Section: Methodsmentioning

confidence: 99%

“…(17). In the first instance, the reactivity of the clusters (10 M) with DTNB (4 M) was measured in 0.2 M Tris⅐HCl, pH 7.4 (12), whereas in the second instance, clusters (5 M) and DTNB (from 0.25 to 1.5 mM) were reacted in 5 mM Tris⅐HCl, pH 7.4, containing 0.1 M KCl (17). All data were analyzed as first-order reactions by plotting ln(A ϱ Ϫ A t ) vs. time.…”

Section: Methodsmentioning

confidence: 99%

“…The rate constant for human Zn 7 -MT-2 (2.8 ϫ 10 observed rate constant of the fast step vs. the concentration of DTNB are linear with a finite intercept (Fig. 6A), indicating both DTNB-dependent and DTNB-independent components with a rate law v ϭ k 1 ϩ k 2 [DTNB] (17). The first-order constants for the DTNB-independent processes (intercept) are k 1␣ ϭ 0.5 ϫ 10 , whereas the second-order rate constants for the DTNB-dependent processes (slopes) are k 2␣ ϭ 1.9 s Ϫ1 ⅐M…”

Section: Comparison Of the Sulfhydryl Reactivity Of The Zinc Clustersmentioning

confidence: 99%

“…17), demonstrating that the influence of the metal on the reactivity of MT with DTNB is negligible. The relationship between DTNB and the observed rate constants in the slow step is nonlinear (Fig.…”

mentioning

confidence: 98%

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Zinc transfer potentials of the α- and β-clusters of metallothionein are affected by domain interactions in the whole molecule

Jiang

Vašák

Vallée

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

129

111

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The ␣-and ␤-polypeptides of human metallothionein (isoform 2), obtained by chemical synthesis, were converted into their respective zinc͞thiolate clusters, and each domain was investigated separately. Proton titration data for the N-terminal ␤-domain fit a simple model with three ionizations of the same apparent pK a value of 4.9 and a collective binding constant for zinc of 5 ؋ 10 ؊12 M at pH 7.0. The zinc cluster in the C-terminal ␣-domain is more stable than that in the ␤-domain. Its pH titration is also more complex, indicating at least two classes of zinc sites with different affinities. The whole molecule is stabilized with regard to the individual domains. Chemical modification implicates lysine side chains in both the stabilization of the ␤-domain cluster and the mutual stabilization of the domains in the whole molecule. The two zinc clusters also differ in the reactivity of their cysteine sulfurs and their potential to donate zinc to an acceptor molecule dependent on its type and characteristics. The isolated ␤-domain cluster reacts faster with Ellman's reagent and is a better zinc donor toward zinc-depleted sorbitol dehydrogenase than is the isolated ␣-domain cluster, whereas the reverse is observed when a chelating agent is the zinc acceptor. Thus, although each cluster assembles independently of the other, the cumulative properties of the individual domains do not suffice to describe metallothionein either structurally or functionally. The two-domain structure of the whole molecule is important for its interaction with ligands and for control of its reactivity and overall conformation.

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Section: Discussioncontrasting

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Comparison Of the Sulfhydryl Reactivity Of The Zinc Clustersmentioning

confidence: 99%

mentioning

confidence: 98%

See 3 more Smart Citations

Zinc transfer potentials of the α- and β-clusters of metallothionein are affected by domain interactions in the whole molecule

Jiang

Vašák

Vallée

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

129

111

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Gold Compounds and Their Applications in Medicine

2009

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An Insight of S‐Nitrosylation of Human GIF

et al. 2005

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Neural growth inhibitory factor (GIF), a member of metallothionein family (metallothionein-3, MT3), was well known by its distinct neural growth inhibitory activity, which is not shown by other MT isoforms. However, till now, people still did not know clearly how GIF exerts its biological functions. Since it has been reported that GIF might serve as NO scavenger and was related to the release of zinc, our study was focused on the interaction of GIF and NO. By studying the reactions of human GIF and human MT1g with SNOC-a type of NO donor, it was found that GIF was more reactive than MT-1g toward SNOC. In order to further figure out if the high reactivity of GIF in this reaction resulted from the acid-base catalysis, several mutants were constructed: E23K, E41G/E43A, E23K/E41G/E43A. By studying their basic properties and the reactions toward SNOC, it was found that the S-nitrosylation of GIF was not only related to the acid-base catalysis, but also to the accessibility of metal-thiolate clusters.

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On the rapid, monophasic reaction of the rabbit liver metallothionein .alpha.-domain with 5,5'-dithiobis (2-nitrobenzoic acid) (DTNB)

Cited by 31 publications

References 1 publication

Zinc transfer potentials of the α- and β-clusters of metallothionein are affected by domain interactions in the whole molecule

Zinc transfer potentials of the α- and β-clusters of metallothionein are affected by domain interactions in the whole molecule

Gold Compounds and Their Applications in Medicine

An Insight of S‐Nitrosylation of Human GIF

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