DsbA family, 2-hydroxychromene-2-carboxylate (HCCA) isomerase subfamily; HCCA isomerase is a glutathione (GSH) dependent enzyme involved in the naphthalene catabolic pathway. It converts HCCA, a hemiketal formed spontaneously after ring cleavage of 1,2-dihydroxynapthalene by a dioxygenase, into cis-o-hydroxybenzylidenepyruvate (cHBPA). This is the fourth reaction in a six-step pathway that converts napthalene into salicylate. HCCA isomerase is unique to bacteria that degrade polycyclic aromatic compounds. It is closely related to the eukaryotic protein, GSH transferase kappa (GSTK).
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