Involved in the degradation of the phenoxypropionate herbicides. Catalyzes the enantiospecific cleavage of the ether bond in the herbicid S-dichlorprop ((S)-2-(2,4-dichlorophenoxy)propionate)(S-2,4-DP) and S-mecoprop ((S)-2-(4-chloro-2-methylphenoxy)propionate)(S-2,4-MCPP). It can also accept (RS)-2-(4-chlorophenoxy)propionate, (RS)-2-(m-chlorophenoxy)propionate and phenoxyacetate derivatives such as 2,4-dichlorophenoxyacetate (2,4-D), however it can only accept 2-oxoglutarate as oxygen acceptor. (S)-2-(4-chloro-2-methylphenoxy)propanoate + 2-oxoglutarate + O2 = 2-methyl-4-chlorophenol + CO2 + pyruvate + succinate (S)-(2,4-dichlorophenoxy)propanoate + 2-oxoglutarate + O2 = 2,4-dichlorophenol + CO2 + pyruvate + succinate Inhibited by divalent cations, most significantly by copper and nickel, and by diethylpyrocarbonate (DEPC). kcat is 50 min(-1) for dioxygenase activity with S-2,4-DP (at pH 6 and 25 degrees Celsius). kcat is 46 min(-1) for dioxygenase activity with S-2,4-MCPP (at pH 6 and 25 degrees Celsius). kcat is 36 min(-1) for dioxygenase activity with 2,4-D (at pH 6 and 25 degrees Celsius). kcat is 17 min(-1) for dioxygenase activity with (RS)-2-(4-chlorophenoxy)propionate (at pH 6 and 25 degrees Celsius). kcat is 15 min(-1) for dioxygenase activity with (RS)-2-(m-chlorophenoxy)propionate (at pH 6 and 25 degrees Celsius). kcat is 1.7 min(-1) for dioxygenase activity with alpha-ketoglutarate (at pH 6 and 25 degrees Celsius). Optimum pH is about 6. Optimum temperature is 25 degrees Celsius. Xenobiotic degradation; 2-(2,4-dichlorophenoxy)propanoate degradation. Monomer. Repressed during growth on high concentrations of 2,4-dichlorophenoxypropionic acid (2,4-DCPP). Belongs to the TfdA dioxygenase family.