Involved in the biodegradation of xenobiotic compounds, such as nitrobenzene and 4-chloronitrobenzene (4-CNB) (PubMed:16517619). CnbZ preferentially catalyzes the deamination of 2-amino-5-chloromuconate (2A5CM) to yield 2-hydroxy-5-chloromuconate (2H5CM). Also able to catalyze the deamination of 2-aminomuconate to yield 2-hydroxymuconate, which spontaneously converts into its keto form, 2-oxalocrotonate. (2Z,4E)-2-aminomuconate + H2O = (2Z,4E)-2-hydroxyhexa-2,4-dienedioate + NH4(+) Cysteine residue modifying agents such as p-chloromercuribenzoate and the SH-binding metals Zn(2+), Ni(2+) and Cu(2+) completely inhibit deaminase activity, whereas Ca(2+), Mg(2+) and the histidine residue-modifying agent diethyl pyrocarbonate inhibit the activity by 23 to 50%. Xenobiotic degradation; 4-chloronitrobenzene degradation. Xenobiotic degradation; nitrobenzene degradation. Monomer. By 4-chloronitrobenzene.