FAQ: Are there any amino acid residues that inhibit or reduce the efficiency of digestion of glutamate residues in a peptide sequence with Endoproteinase GluC? The site I want to digest has a glutamate residue followed by a proline residue and some enzymes are inhibited by the presence of a proline after the hydrolysis site.

We don't have a fluorescent substrate to test out the actual rate of cleaveage of EP by Endoproteinase GluC, although we know that this site indeed gets cut by GluC, albeit possibly at a reduced rate. Other than in the case of Asp residues, which we know have a cleaveage rate 100-300X slower than cleavage at Glu, we know of no other amino acid residues that inhibit or reduce the efficiency of digestion with Endoproteinase GluC other than the sequence EE within a peptide context where the E-E linkage is cleaved at a slower rate.