Production, purification and characterization of two proteinaceous hen-egg-white lysozyme inhibitors from Pseudomonas aeruginosa M-1001

Abstract

Two proteinaceous lysozyme inhibitors, hen-egg-white lysozyme inhibitors F-I and F-II, were isolated from the culture broth of a bacterial strain identified as Pseudomonas aeruginosa M-1001. Maximum lysozyme inhibitory activity was obtained when the bacterium was grown aerobically in a medium consisting of 0.25% glucose, 0.25% beef extract, 0.25% polypepton, 1.0% sodium L-glutamate, and 1.0% soluble starch (pH 7.0) at 37 degrees C after 20-24 hrs. F-I and F-II were purified 20 and 7.5-fold, respectively, from the culture supernatant of P. aeruginosa M-1001 by ammonium sulfate fractionation, DEAE-Sepharose CL-6B column chromatography, and Sephacryl S-200 gel chromatography. The molecular weights of F-I and F-II were estimated to be about 57,000 and 33,000, by SDS-PAGE, respectively. F-I was stable in a pH range between 6 and 10 and below 50 degrees C. F-II was stable in a pH range between 6 and 11 and below 40 degrees C. Many Gram-positive bacteria were found to be inhibited by the crude lysozyme inhibitors.