There are no such endo N-acetylglucosaminidases that will do that reaction. However, there is an endo-alpha-N-acetylgalactosaminidase that will with the substrate Gal-beta 1,3 GalNAc alpha -pNP (Sigma Chemicals- USA). See http://www.prozyme.com/glycoenzymes/ for the enzyme (endo-O-Glycosidase)