Polarography as a Tool in Peptide and Protein Analysis: Studies on Metal-Chelating Substances Induced by Cadmium in the Algae Pheodactylum tricornutum and the Graminae Agrostis capillaris

Nyberg, Sister M.Helen Therese; Zhou, Lianbi

doi:10.1006/eesa.1995.1095

Cited by 8 publications

(7 citation statements)

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“…The hypothesis reported by Nyberg and Zhou [9], that Cd is bound to phytochelatins both weakly, to a single cysteinyl group, as well as strongly, to several cysteine moieties, does not agree with our results on the pH-dependent Cd removal which indicates that Cd is bound to phytochelatins in only one, strong, binding state.…”

Section: Peak Potential As a Function Of Phcontrasting

confidence: 99%

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Polarographic Behavior of Metal Phytochelatin Complexes

Scarano

Morelli

1998

Electroanalysis

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The polarographic characteristics of metal-phytochelatin complexes (Me-PC) extracted from the marine alga Phaeodactylum tricornutum were investigated by the use of differential pulse polarography (DPP) at dropping mercury electrode (DME). Four metal-phytochelatin complexes differing for the metal bound, namely Cd-, Pb-, Zn-and Cu-PC, were studied, and their polarographic behavior was compared with that of Cd,Znthionein and Zn-thionein of mammalian origin. The polarographic characteristics of Me-PC exhibit a dependence on the metal bound to the peptides and on the pH of the solution. Both the organic and inorganic part of Me-PC are electroactive and give polarographic responses depending on their chemical form in solution. Dissociation and formation processes were investigated. The order of stability of the complexes was KZn¹PC . The same electrochemical mechanisms were found to characterize both the polarographic behavior of metallothioneins and metal-phytochelatin complexes.

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Section: Peak Potential As a Function Of Phcontrasting

confidence: 99%

“…Polarographic information on Me-PC is very poor and the only investigation found in the literature regarded the Cd binding peptide produced by the alga Phaeodactylum tricornutum and the graminae Agrostis capillaris exposed to Cd [9]. Two main peaks at ¹0.55 and ¹0.93 V were detected at pH 8 in potassium phosphate buffer.…”

Section: Introductionmentioning

confidence: 97%

Polarographic Behavior of Metal Phytochelatin Complexes

Scarano

Morelli

1998

Electroanalysis

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“…In Table 1 (Figures 1 and 3), it is clear that both signals (at −0.60 V and about −0.73 V) are related to the electrode processes which involve cadmium [9]. Cd-cysteinate is chemically inert type of complex.…”

Section: Centrationmentioning

confidence: 99%

Electrochemical Study of Cadmium (II) Complexation with Cysteine

Ramani¹,

Raspor²,

Arbneshi³

2013

AJAC

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The complexation of Cd with cysteine has been investigated at pH ~9, and in constant ionic medium 0.59 M NaNO 3 and borate buffer. Reduction signals of the hydrated Cd 2+ and Cd-cysteinate complex were resolved on the potential scale during amperometric titration of 2 × 10 −6 M Cd 2+ with cysteine and cysteine with Cd 2+ , in a differential pulse (DP) mode on HMDE. The 1:1 molar ratio of Cd 2+ to cysteine, and cysteine to Cd 2+ , was defined for Cd-cysteinate complex formed under the defined conditions. The appearance of the prepeak on the Cd-cysteinate reduction signal is showed, as the result of cysteine adsorption in reduced form. From the mass balance equations, the stoichiometric stability constants of Cd-cysteinate complex were calculated. Under various experimental conditions, comparable log K values were obtained. The grand average log K = 7.83 M −1 refers to 0.59 M ionic strength and 23˚C.

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“…A range of methods have been developed for determination of thiols, including electrochemical methods such as cathodic stripping voltammetry and polarography [37][38][39][40][41][42][43], capillary electrophoresis (CE) equipped with electrochemical detection [44], laser-induced fluorescence detection [45] or photodiode array [46,47], and HPLC with UV/vis detection [48,49], electrochemical detection [50][51][52], fluorescence detections [3,6,28,[53][54][55][56][57][58][59][60][61][62][63][64][65][66][67] or inductively coupled plasma-mass spectrometry (ICP-MS) and electrospray-mass spectrometry (ES-MS) [68][69][70][71][72][73][74][75][76][77][78][79][80]. These methods were selective and ...…”

Section: Introductionmentioning

confidence: 99%