glucosamine, a main structural component of fungal cell wall and
exoskeleton of many invertebrates such as nematodes and insects.
They belong to family 18 and 19 O- glycoside hydrolases. Both
families of chitinases differ in the catalytic mechanism of hydrolysis.
Chitinases belonging to family 18, catalyze substrate-assisted
and form an intermediate oxazolium ion. In comparison, the acidic
catalysis, characteristic for chitinases belonging to family 19, form
an intermediate oxocarbenium ion