Characterization of an elastase inhibitor produced by Streptomyces lavendulae SMF11

Abstract

An elastase inhibitor, SMFEI02, was isolated from culture broth of Streptomyces lavendulae SMF11. The inhibitor was purified by ultrafiltration followed by XAD-7 column and Dowex-1 anion-exchange chromatographies, and preparative HPLC. The molecular formula was determined to be C14H16N2O2 (MW 244) by HRFAB-MS analysis. The inhibitor was identified to be a diketopiperazine cyclo(S-Phe-S-Pro) by the optical rotation value and NMR spectral data, and showed inhibitory activities for trypsin, chymotrypsin, cathepsin B, and papain as well as elastase with the K(i) values ranging from 1.78 mM to 2.86 μM. The inhibition showed a competitive mode for elastase, chymotrypsin, and cathepsin B, whereas it showed a noncompetitive mode for trypsin and papain.