Characterization of the wild-type form of 4a-carbinolamine dehydratase and two naturally occurring mutants associated with hyperphenylalanemia

A study was conducted to characterize the forms of phenylalanine hydroxylase-stimulating protein/DCoH found in patients with hyperphenylalanemia and to compare them with the wild-type enzyme in the GenBank. Gene cloning revealed that mutant C82R is similar to the wild-type enzyme in that both are heat stable and forms a tetramer. However, C82R is more susceptible to proteolysis and are expressed in lower levels in transfected mammalian cells than the wild-type protein.