title: Effect of chlorination on the protein phosphatase inhibition activity for several microcystins.
abstract: Microcystins are of particular concern due to their toxicity to both humans and animals and may be the most prominent cyanotoxin observed in freshwater. Although a number of studies have investigated the fate of microcystins and other algal toxins through drinking water treatment facilities, measurement of their potential for toxic activity after chlorination, a popular form of treatment in the United States, has not been investigated. In this study, six microcystin variants are subjected to chlorine oxidation. The degradation of each microcystin variant is measured by liquid chromatography/mass spectrometry simultaneously with protein phosphatase inhibition (PPI) response over reaction time with chlorine. Results show that inhibition is dependent on the incorporated amino acid residues, their placement within the microcystin structure, as well as pH. This pH dependence may have practical implications to such activities such as drinking water treatment when the pH is usually adjusted to around 8. Namely, at this pH, even with chlorine addition for disinfection, PPI activity may not be totally eliminated even when the initial MYCs are eliminated.
authors.affiliation: Office of Research and Development, National Risk Management Research Laboratory, Water Supply and Water Resources Division, Treatment Technology Evaluation Branch, United State Environmental Protection Agency, 26 W. Martin Luther King Drive, Cincinnati, OH 45268, USA. Electronic address: mash.heath@epa.gov.
authors.forename: H
authors.initials: H
authors.lastname: Mash
authors.affiliation: University of Cincinnati, 2600 Clifton Ave, Cincinnati, OH 45220, USA.
authors.forename: A
authors.initials: A
authors.lastname: Wittkorn
mesh_terms: D000818:Animals; D002713:Chlorine / Q000737:chemistry; D054879:Halogenation; D052998:Microcystins / Q000737:chemistry*; D010749:Phosphoprotein Phosphatases; D018508:Water Purification
chemical_list: D052998:Microcystins; D002713:Chlorine; D010749:Phosphoprotein Phosphatases
keywords: Algaltoxin; Chlorination; Microcystin; Protein phosphatase inhibition