Structural modifications imparting reduced toxicity in microcystins from Microcystis spp.

Protein Phosphatase Inhibition Assay for Detection of Microcystins in Lake Water and Microcystis Cultures.

“…Figure 4 shows the changes in concentration of microcystins in the culture fluid (Fig. 1), which correlated well with LD50 estimated by mouse assays6, 13,23,29). Therefore, the protein phosphatase inhibition assay could be used to estimate toxicity of microcystin of natural water samples in place of the mouse bioassay.…”

A Molecular Basis for Different Interactions of Marine Toxins with Protein Phosphatase-1

“…The rigid saddle-shaped backbone provides the proper framework for the hydrophobic, ionic, and covalent interactions between microcystin-LR and the phosphatase. These interactions involve the Adda and Masp/Glu residues, which are essential for inhibition (9,13,22), and the Mdha residue, which is required for secondary covalent linkage.…”

Identification and estimation of microcystins in freshwater mussels

“…The differences among the components are mainly due to substitution of two L-amino acids and the degree of methylation on d-MeAsp and Mdha. Modification to Adda was shown to affect the lethal toxicity [Stotts et al, 1993].…”