SNA-8073-B, a New Isotetracenone Antibiotic Inhibits Prolyl Endopeptidase

I. Fermentation, Isolation and Biological Properties

Abstract

SNA-8073-B, an inhibitor of prolyl endopeptidase isolated from the broth filtrate of Streptomyces sp. SNA-8073, is a new isotetracenone antibiotic. It was purified by ethyl acetate extraction, silica gel column chromatography and high performance liquid chromatography on ODS column. SNA-8073-B has the molecular formula of C₂₀H₁₆O₅ and is a stereoisomer of SNA-8073-A (fujianmycin B, rubiginone A₂). SNA-8073-B inhibited prolyl endopeptidase of Flavobacterium non-competitively (IC₅₀=8.9μM) when Z-Gly-Pro-pNA was used as a substrate, but SNA-8073-A did not show any inhibition even at 60μM.