This enzyme belongs to the family of oxidoreductases, specifically those acting on single donors with O2 as oxidant and incorporation of two atoms of oxygen into the substrate (oxygenases).

The systematic name of this enzyme class is protocatechuate:oxygen 3,4-oxidoreductase (decyclizing).

This enzyme has been found effective at improving organic fluorophore-stability in single-molecule experiments.

generally require further purification to remove strong contaminating nuclease activity.

As of late 2007, 37 structures have been solved for this class of enzymes, with PDB accession codes 1EO2, 1EO9, 1EOA, 1EOB, 1EOC, 1YKK, 1YKL, 1YKM, 1YKN, 1YKO, 1YKP, 2BUM, 2BUQ, 2BUR, 2BUT, 2BUU, 2BUV, 2BUW, 2BUX, 2BUY, 2BUZ, 2BV0, 2PCD, 3PCA, 3PCB, 3PCC, 3PCD, 3PCE, 3PCF, 3PCG, 3PCH, 3PCI, 3PCJ, 3PCK, 3PCL, 3PCM, and 3PCN.