2-Hydroxyl-6-oxo-6-phenylhexa-2,4-dienoic acid hydrolase (BphD) hydrolyses an unusual C-C bond of 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid (HOPDA) to produce benzoic acid and 2-hydroxy-2,4-pentadienoic acid (HPD). HOPDA is an aromatic compound generated in a biphenyl/polychlorinated biphenyl (PCB) degradation pathway of bacteria.
It is a member of the alpha/beta hydrolase superfamily and has the canonical Ser-His-Asp triad. There has been a lot of debate as to the exact mechanism of this enzyme.