Poststatin, a new inhibitor of prolyl endopeptidase, produced by Streptomyces viridochromogenes MH534-30F3. I. Taxonomy, production, isolation, physico-chemical properties and biological activities.

Poststatin, a new inhibitor of prolyl endopeptidase (PEP) was discovered in the fermentation broth of Streptomyces viridochromogenes MH534-30F3. It was purified by Diaion HP-20, Sephadex LH-20 and YMC-gel (ODS-A) column chromatography and then isolated as a colorless powder. Poststatin has the molecular formula C26H47N5O7. The IC50 value of poststatin against the PEP of partially purified porcine kidney was 0.03 microgram/ml. It has low acute toxicity. No deaths occured after iv injection of 250 mg/kg of this agent to mice.