Leandro J, Leandro P, Flatmark T. Heterotetrameric forms of human phenylalanine hydroxylase: Co-expression of wild-type and mutant forms in a bicistronic system. Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease. 2011 May;1812(5):602–12. doi: 10.1016/j.bbadis.2011.02.001.