An angiotensin-converting enzyme-inhibitory metabolite with partial structure of microginin in a cyanobacterium Anabaena fertilissima CCC597, producing fibrinolytic protease

摘要

Whole cell matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) of Anabaena fertilissima CCC597 revealed the presence of a microginin (M (r) = 565 Da), which was purified using ODS C18 solid-phase extraction followed by quaternary methyl ammonium (QMA)-ion exchange and reverse-phase liquid chromatography. Its partial structure was deduced upon LC-MS/MS as beta-amino-alpha-hydroxy-decanoic acid-Ala-MeLeu-Tyr. Microginin-565 inhibited rabbit angiotensin-converting enzyme activity at an apparent IC50 = 9.8 mu M.