Complexing of copper ion by ergothioneine.

Release of weak and strong copper-complexing agents by algae1

By means of potentiometric titrations, the copper-complcxing properties of organic compounds released by 21 algal species are characterized. Most eucaryotic species relcascd measurablc amounts (lo-” M) of copper-complexing agents that could be modeled as weak organic acids with log{*&.,,,} = 0.5. Of seven blue-green algal species studied, four produced about 5 x lo+ M concentrations of strong c...

Kinetics of copper(II) uptake by apoazurin in complexing media.

We have studied the kinetics of copper uptake by apoazurin in imidazole and 1-methylimidazole buffers in the pH range of 7-9 with mu = 0.5 M and copper(II) in large excess. The reaction has been monitored by measuring the visible absorbance and circular dichroism as a function of time. The uptake occurs in a stepwise fashion, and at least two intermediates are implicated. Overall, the rate of u...

Tracking an ion complexing agent within bilayers

Determination of Copper Content of Human Blood Plasma by an Ion Selective Electrode based on a New Copper-Selectophore

A new selectophore was introduced for Cu2+ ions. Spectroscopic studies showed a selectivity of a new organic compound (L) toward copper ions and several transitional metal ions. Hence, L was utilized in designing several ion selective electrodes for these cations. In practice, Cu2+ ion selective electrode behaved Nernstian (slope of 27.95±0.3 mV decade-1) over a...

Fluxes of copper-complexing ligands from estuarine sediments

Most studies of the organic complexation of Cu in natural waters have focused on distributions and processes in the water column, where a significant fraction of Cu-complexing ligands may be biologically produced. We present direct evidence for a flux of Cu-complexing ligands from estuarine sediments, demonstrating that sediments are a significant, yet previously unrecognized source of the liga...