Abstract
Secondary metabolites produced by water-blooming cyanobacteria in eutrophic waters include some potent hepatotoxins. These compounds also have tumour-promoting properties, attributable to their inhibition and activation of protein phosphatases and kinases respectively. The inhibitory effect of these toxins on protein phosphatases have been employed in a commonly used radiometric assay, involving the use of a 32P-labeled substrate, for the detection and quantitation of these compounds. This paper investigates and describes a colorimetric method in which the activity of protein phosphatase 2A is determined by measuring the rate of colour production from the release of yellow p-nitrophenol using p-nitrophenyl phosphate as the substrate. Results of this study suggest that the colorimetric protein phosphatase inhibition assay is a simple, inexpensive tool for screening substances that may have tumour-promoting characteristics in aquatic systems. The detection limit of the colorimetric method is comparable to the radiometric assay.
Original language | English |
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Pages (from-to) | 1113-1122 |
Number of pages | 10 |
Journal | Chemosphere |
Volume | 38 |
Issue number | 5 |
DOIs | |
Publication status | Published - Feb 1999 |
Externally published | Yes |