Human PanK-II isoforms PanK1α, PanK1β, PanK2, and PanK3 have a common, highly homologous catalytic core of approximately 355 residues. PanK1α and PanK1β are both encoded by the "PANK1" gene and have the same catalytic domain of 363 amino acids, encoded by exons 2 through 7. The PanK1α transcript starts with exon 1α that encodes a 184-residue regulatory domain at the N-terminus. This region allows for feedback inhibition by free CoA and acyl-CoA and regulation by acetyl-CoA and malonyl-CoA. On the other hand, the PanK1β transcript starts with exon 1β, which produces a 10-residue N-terminus that does not include a feedback regulatory domain.