Isolation of Adda from microcystin-LR by microbial degradation.

The intact Adda was isolated from microcystin-LR by a microbial degradation using an isolated Sphingomonas strain, B-9. The reaction of microcystin-LR with cell extract of this strain proceeded smoothly to give the final degradation product by way of two intermediates, linearized microcystin-LR and a tetrapeptide. The purified Adda that was structurally characterized using various spectral data did not show the toxicity to mice or inhibition to protein phosphatase activity in contrast to the native toxin.