Fig. 17.

Proposed gentisate cleavage mechanism, adapted from references [97], [101]. The principle mechanism of Harpel and coworkers suggest initial activation of O₂ by electron transfer from Fe(II), followed by attack of the activated oxygen species at C2 of the substrate, resulting in the peroxidate intermediate. The 3-His metal binding motif and metal coordinated water molecules as well as outer shell residues that assist in catalysis are inferred based on the crystal structure [100], [101].