This family contains a diverse set of proteins with a thioredoxin-like structure pfam00085. This family also includes 2-hydroxychromene-2-carboxylate (HCCA) isomerase enzymes catalyze one step in prokaryotic polyaromatic hydrocarbon (PAH) catabolic pathways. This family also contains members with functions other than HCCA isomerization, such as Kappa family GSTs, whose similarity to HCCA isomerases was not previously recognized. Some members have been annotated as dioxygenases, dehydrogenases, or putative glycerol-3-phosphate transfer proteins, but are most likely HCCA isomerase enzymes.
Jiyao W et al.(2023). "The conserved domain database in 2023.",