PURIFICATION AND CHARACTERIZATION OF THE CHITINASE (CHIA) FROM ENTEROBACTER SP G-1

Enterobacter sp, G-1 which produces chitinolytic and chitosanolytic en zymes, was previously isolated in our laboratory, One major chitinase, designated ChiA, was purified 42.9-fold from a culture filtrate of En terobacter sp, G-1. To purify the chitinase, ammonium sulfate fraction ation, DEAE-Sephadex A-50 column chromatography, and gel filtration on Sephadex G-100 column chromatography were used, The ChiA protein had a molecular weight of 60,000 estimated by SDS polyacrylamide gel elect rophoresis and an isoelectric point of 6.6, The optimal pH and optimal temperature of ChiA against colloidal chitin were pH 7.0, and 40 degr ees C, respectively. The purified ChiA degraded colloidal chitin mainl y to GlcNAc(2) with a small amount of GlcNAc(3) and GlcNAc(4). ChiA hy drolyzed flaked chitin, colloidal chitin, and ethylenglycol chitin, bu t did not hydrolyze carboxymethyl cellulose (CMC), nor >90% deacetylat ed flaked chitosan, The chitinase activity was 42% inhibited by 10 mM EDTA, but was not inhibited by Ca2+ (<50 mM) or NaCl (<400 mM). The pu rified ChiA hydrolyzed colloidal chitin and chitin-related compounds i n an endo splitting manner.