TMC-52A to D, Novel Cysteine Proteinase Inhibitors, Produced by Gliocladium sp.

Abstract

New cysteine proteinase inhibitors, TMC-52A, B, C, and D, were isolated from the fungal fermentation broth. On the basis of a taxonomical study, the producing strain, F-2665, was characterized as Gliocladium sp. Spectroscopic analyses and chemical degradation have shown TMC-52A to D to be epoxysuccinyl peptides. TMC-52A to D strongly inhibited cysteine proteinases, in paticular, cathepsin L with IC₅₀ values of 13 nM, 10 nM, 10 nM, and 6 nM, respectively.