A chitinase gene from Bacillus cereus was cloned and expressed in Escherichia coli. The purified recombinant chitinase had much higher (128 fold) specificity to pNP-beta-(GlcNAc)(3) than to pNP-beta-(GlcNAc), suggesting endochitinase. Thirty-three amino acids in the N-terminal were recognized and cut off during expression, which consequently made the M(r) not correspond to that predicted.