What are chitin/chitosan hydrolases and chitin/chitosan depolymerases?
The term chitosan hydrolase summarily includes all enzymes able to hydrolytically cleave the β-1,4-glycosidic linkage within chitosan molecules, i.e. including chitinases and chitosanases, but also glucosaminidases and N-acetylglucosaminidases. Thus, it does not include chitin monooxygenases as these are lytic rather than hydrolytic enzymes (i.e., no water molecule is added upon cleavage of the glycosidic bond). It also typically does not include chitin deacetylases even though these are also performing a hydrolytic cleavage. The term chitin/chitosan depolymerase summarily includes all enzymes able to depolymerize chitin and/or chitosan by cleaving the β-1,4-glycosidic linkage between their monomeric building blocks. Thus, it includes chitin/chitosan hydrolases, i.e. chitinases, chitosanases, glucosaminidases, and N-acetylglucosaminidases, and also the lytic chitin monooxygenases, but it clearly excludes chitin deacetylases. Alternative names for chitin/chitosan depolymerases would be chitolytic (chitinolytic/chitosanolytic) or chitoclastic (chitinoclastic/chitosanoclastic) enzymes.