Chitinase from Enterobacter sp. NRG4: Its purification, characterization and reaction pattern

Enterobacter sp. NRG4 was shown to excrete chitinase into the culture supernatant when cultivated in medium containing chitin. A 60 kDa extracellular chitinase was purified to homogeneity and characterized. The enzyme hydrolyzed swollen chitin, colloidal chitin, regenerated chitin and glycol chitin but did not hydrolyze chitosan. The chitinase exhibited Km and Vmax values of 1.43 mg ml and 83.33 μM μg h for swollen chitin, 1.41 mg ml 1 and 74.07 μM μg h for colloidal chitin, 1.8 mg ml and 40 μM μg h for regenerated chitin and 2.0 mg ml 1 and 33.33 μM μg h for glycol chitin, respectively. The optimal temperature and pH for activity were 45oC and pH 5.5, respectively. Mg, K and Ca stimulated chitinase activity by 13, 16 and 18%, respectively whereas Cu, Co, Ag and Hg inhibited chitinase activity by 9.7, 15, 22 and 72.2%, respectively at 1 mM concentration. N-bromosuccinamide (NBS) at 1 mM and iodoacetamide at 10 mM concentration completely