Kasumigamide, an antialgal peptide from the cyanobacterium Microcystis aeruginosa.

Kasumigamide (1), a novel antialgal tetrapeptide containing an N-terminal alpha-hydroxy acid, was isolated from the freshwater cyanobacterium Microcystis aeruginosa (NIES-87). Its structure was elucidated by two-dimensional (1)H-(1)H and (1)H-(13)C NMR correlation experiments and confirmed by mass spectral and amino acid analyses. The absolute stereochemistry of 1 was determined by chemical studies. This peptide showed an antialgal activity against the green alga Chlamydomonas neglecta (NIES-439).