The UDP-glucose:glycoprotein glucosyltransferases 1 and 2 (UGGT1 and 2) are able to distinguish proteins with minor folding defects in the ERQC and reglucosylate them, by transferring a glucose (from dolichyl beta-D-glucosyl phosphate, DbGP) onto the alpha 1,3 mannose of the b (or c, not shown here) branch (Arnold et al. 2000, Arnold et al. 2003). The major affinity of these enzymes for proteins with minor folding defects has been demonstrated, but the exact mechanism that enable them to distinguish proteins with major and minor defects is still unknown (Pearse et al. 2008).