Endo-beta-N-acetylglucosaminidases are bacterial chitinases that hydrolyze the chitin core of various asparagine (N)-linked glycans and glycoproteins. The endo-beta-N-acetylglucosaminidases have a glycosyl hydrolase family 18 (GH18) catalytic domain. Some members also have an additional C-terminal glycosyl hydrolase family 20 (GH20) domain while others have an N-terminal domain of unknown function (pfam08522). Members of this family include endo-beta-N-acetylglucosaminidase S (EndoS) from Streptococcus pyogenes, EndoF1, EndoF2, EndoF3, and EndoH from Flavobacterium meningosepticum, and EndoE from Enterococcus faecalis. EndoS is a secreted endoglycosidase from Streptococcus pyogenes that specifically hydrolyzes the glycan on human IgG between two core N-acetylglucosamine residues. EndoE is a secreted endoglycosidase, encoded by the ndoE gene in Enterococcus faecalis, that hydrolyzes the glycan on human RNase B.