EI-1511-3, EI-1511-5 AND EI-1625-2, NOVEL INTERLEUKIN-1-BETA CONVERTING-ENZYME INHIBITORS PRODUCED BY STREPTOMYCES SP E-1511 AND E-1625 .3.BIOCHEMICAL-PROPERTIES OF EI-1511-3, EI-1511-5 AND EI-1625-2

EI-1511-3, -5 and EI-1625-2, novel interleukin-1 beta converting enzym e OCE) inhibitors from the culture broths of Streptomyces sp. selectiv ely inhibited the recombinant human ICE activity with IC50 values of 0 .09, 0.38 and 0.2 mu M, respectively, without inhibiting elastase and cathepsin B. Manumycin G, ent-alisamycin, U-56,407, and manumycin A an d B isolated simultaneously from the same strains also inhibited ICE. EI-1511-3, -5 and EI-1625-2 also inhibited mature interleukin-1 beta s ecretion from THP-1 cells with IC50 values of 5.4, 3.6 and 2.2 mu M, r espectively. In this article, biological properties of EI-1511-3, -5 a nd EI-1625-2 and, in addition, properties of manumycin-related compoun d are described.