Colorimetric protein phosphatase inhibition assay of laboratory strains and natural blooms of cyanobacteria: comparisons with high-performance liquid chromatographic analysis for microcystins
- 15 August 1997
- journal article
- research article
- Published by Oxford University Press (OUP) in FEMS Microbiology Letters
- Vol. 153 (2) , 465-473
- https://doi.org/10.1016/s0378-1097(97)00290-5
Abstract
Microcystins are cyclic heptapeptide hepatotoxins commonly produced by bloom-forming genera of cyanobacteria. These toxins are potent and specific inhibitors of protein phosphatases 1 and 2A. We have optimised a rapid, simple and sensitive colorimetric protein phosphatase 1 inhibition assay, utilising the activity of protein phosphatase 1 as expressed in a recombinant strain of Escherichia coli, towards the chromogenic substrate, p-nitrophenyl phosphate. A standard curve for the inhibition of protein phosphatase 1 by microcystin-LR was constructed with an IC50 of about 38 ng ml−1 and a limit of detection of 10–20 ng ml−1. Twenty-three laboratory-grown strains and 25 natural bloom samples of cyanobacteria were analysed by high-performance liquid chromatography for microcystins and by the protein phosphatase 1 inhibition assay. Agreement for the microcystin contents of the samples detected by high-performance liquid chromatography and the protein phosphatase 1 inhibition assay showed good correlation (R2 > 0.93, P<0.0001). The suitability of the colorimetric protein phosphatase 1 inhibition assay as a screen for cyanobacterial microcystins is discussed.Keywords
This publication has 0 references indexed in Scilit: