Interaction of halides with CuZn superoxide dismutases

✍ Scribed by E. Argese; P. Viglino; A. Rigo

• Publisher: Elsevier Science
• Year: 1980
• Tongue: English
• Weight: 110 KB
• Volume: 40
• Category: Article
• ISSN: 0020-1693
• DOI: 10.1016/s0020-1693(00)92155-8

✦ Synopsis

The measurement of copper concentrations much lower than ppb is a good example of these applications. For this purpose the polarographic [6] and the pulsed NMR techniques

[2] appear very suitable since they can sense superoxide concentrations of the order of 10-r' and 10m8 M respectively.

Using these techniques, and owing to the very high affinity of the copper ion for its native site, the binding of Cu++ to the copper-free enzyme has been easily followed in a variety of experimental conditions. In particular the addition of known amounts of Cu++ to the copper depleted superoxide dismutase, at [Cu"] /[protein] < 0.1, causes a linear and reproducible increase of both the activity and the relaxivity after few minutes incubation.

The method results to be highly specific for the Cu++ and allows, as measured by the polarographic activity and by r9F relaxivity, to detect the ion with sensitivity of the order of lo-" and 2 X lo-* M respectively.