Two novel biological active modified peptides from the cyanobacterium Microcystis sp.

Two novel biologically active short peptides, aeruginosins KY642, KY608 and the known aeruginosin 98A were isolated from the cyanobacterium Microcystis sp. strain (IL-323), which was collected from a water reservoir near Kfar-Yehoshua, Valley of Armageddon, Israel. Aeruginosins KY642, KY608 and 98A are linear modified peptides containing four building blocks, one of which is the modified amino acid, Choi (2-carboxy-6-hydroxyoctahydroindole). Aeruginosin KY642 and aeruginosin KY608 inhibit the activity of the photolytic enzyme trypsin with IC50 of 1.4 and 1.7 μg/mL, respectively.

Two novel biologically active short peptides, aeruginosins KY642, KY608 and the known aeruginosin 98A were isolated from the cyanobacterium Microcystis sp. strain (IL-323).