Determination of the complex stability of zinc with carbonic anhydrase in sea-water.

Sarthou, G., van den Berg, C. M. G. and Riebesell, Ulf (2001) Determination of the complex stability of zinc with carbonic anhydrase in sea-water. Analyst, 126 (11). pp. 2036-2039. DOI 10.1039/b105364g.

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Abstract

Carbonic anhydrase (CA) is inactive unless associated with zinc, with possible substitution by cobalt. In this work, the complexation of zinc by CA was determined in sea-water using cathodic stripping voltammetry (CSV) with ligand competition. The zinc was found to be released from the CA over a period of 3 h when equilibrated with a competing complexing ligand and the complex was re-formed with the CA when zinc was added. A value of 8.90+/-0.27 was found for logK'ZnCA where K'ZnCA is the conditional stability constant for the complex of Zn2+ with CA in pH 8 sea-water. A value for the molecular weight of CA was calculated from its equivalent ligand concentration (in nM) obtained by titrations with zinc at various CA concentrations (1-4 mg l(-1)). The value found (34740 g mol(-1)) for the molecular weight is consistent with values found previously by other methods (29000-31000 g mol(-1)) confirming that the stoichiometry of the complex between zinc and CA is 1:1. This work confirms that the zinc-CA complex is reversible and that the interaction between zinc and CA can be determined using CSV with ligand competition.

Document Type: Article
Additional Information: WOS:000172167400039
Keywords: CATHODIC STRIPPING VOLTAMMETRY; INORGANIC CARBON; PHOTOSYNTHESIS; SPECIATION; EVOLUTION; CHLORELLA; SEAWATER; CO2; R.V. Discovery 221
Research affiliation: OceanRep > GEOMAR > FB2 Marine Biogeochemistry
AWI
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1039/b105364g
ISSN: 0003-2654
Projects: MAS3, MERLIM
Date Deposited: 18 Feb 2008 17:25
Last Modified: 25 Apr 2016 07:37
URI: http://oceanrep.geomar.de/id/eprint/5310

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