Studies on the chitinolytic enzymes of Streptomycetes 2- Purification and characterization of chitinase enzyme from a chitin-degrading Streptomyces cellulosae [F-2] strain

ABSTRACT

The chitinase enzyme of Streptomyces cellulose [F-2] was purified 18.06-fold with overall yield of 23.7% of the original activity [cell free filtrate] and specific activity 294.3 units/mg protein by ammonium sulfate fractionation [60-80% saturation], ion-exchange chromatography, [DEAE-Cellulose] and sephadex G-200 gel filtration. The enzyme was characterized by demonstration of optimum activity at 35C and pH 7.0. It was stable at 35C and pH 7.0. The enzyme activity was slightly stimulated by Ca2+, Zn2+, Mg2+, Mn2+ and Fe2+ ions, but Na+ and K+ ions did not exert any effect on the enzyme activity which was inhibited by Cu2+, Hg2+, Ag+ ions as well as EDTA, Na- azide, L-cysteine, KCN, iodine, KMnO4 and iodoacetic acid. Addition of 1.5% [w/v] substrate [colloidal chitin] to the purified enzyme liquor led to complete stabilization of the enzyme when stored at 4C [refrigerator] for a period extended to 180 days and for a period of 35 days at room temperature. The antifungal activity of the purified chitinase enzyme was also studied