CYANOPEPTOLIN-S, A SULFATE-CONTAINING DEPSIPEPTIDE FROM A WATER BLOOMOF MICROCYSTIS SP

A new sulfated, cyclic depsipeptide, called cyanopeptolin S, from Micr ocystis sp. was isolated from a water bloom in the Auensee/Leipzig (Ge rmany). The depsipeptide had a relative molecular mass of 925 and cont ained L-arginine, L-threonine, L-isoleucine, N-methyl-L-phenylalanine, a L-glutamic acid-delta-aldehyde ring system and a sulfated D-configu rated glyceric acid as a side chain. The structure was elucidated by m eans of two-dimensional H-1 and C-13 nuclear magnetic resonance spectr oscopy, fast atom bombardment mass spectroscopy, Fourier transformed i nfrared spectroscopy and combined gas-liquid chromatography/mass spect rometry. Cyanopeptolin S inhibited trypsin with an IC50 less than or e qual to 0.2 mu g ml(-1).