Figure 17.13A.5.

PNGase F and endoglycosidase-sensitive bonds in the core of N-linked glycans. PNGase F is a glycoamidase that severs the bond between GlcNAc and Asn, liberating the entire sugar chain and converting Asn into Asp. The endoglycosidases (H, D, and Fs) cleave the bond between the two GlcNAc residues in the core region, leaving one GlcNAc still bound to the protein. The differential specificity of the endoglyosidases is based on the structure of the sugar chain in a fully denatured protein. Incomplete denaturation may not expose all sensitive linkages. X and Y are unspecified sugar residues. For the color version of the figure go to http://www.currentprotocols.com/protocol/mb1713a.