Bladt, Tanja Thorskov1; Kalifa-Aviv, Sivan4; Larsen, Thomas Ostenfeld1; Carmeli, Shmuel4
1 Department of Systems Biology, Technical University of Denmark2 Natural Product Chemistry, Department of Systems Biology, Technical University of Denmark3 Tel Aviv University4 Tel Aviv University
Three new micropeptins, micropeptin KR1030, KR1002 and KR998 and the known microcyclamide GL546A were isolated from the extract of Microcystis sp. bloom material collected in Kabul Reservoir, Israel. The planar structures of the compounds were determined by homonuclear and inverse-heteronuclear 2D-NMR techniques as well as high-resolution mass spectrometry. The absolute configuration of the asymmetric centres of the amino acids was studied using Marfey's method for HPLC. The inhibitory activity of the compounds was determined for the serine proteases: trypsin, chymotrypsin and elastase.