Kinetic and stability analysis of PKU mutations identified in BH4-responsive patients

Mol Genet Metab. 2005 Dec:86 Suppl 1:S11-6. doi: 10.1016/j.ymgme.2005.06.009. Epub 2005 Aug 8.


From all the different molecular mechanisms put forward to explain the basis of BH4 responsiveness in PKU patients, a clear picture is now emerging based on the results from expression studies performed with a number of missense mutations identified in patients with a positive response in BH4 loading tests. Two of the proposed mechanisms, namely decreased binding affinity of the mutant proteins for the natural cofactor and stabilization effect of BH4, have been confirmed for several PKU mutations and the results are reviewed here. The actual view supports a multifactorial basis of the response, highlighting the necessity of detailed in vitro characterization of each mutant PAH protein. Several of the confirmed molecular mechanisms may be operating simultaneously, as exemplified in the data presented, and this may result in different degrees of BH4 responsiveness.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Biopterins / analogs & derivatives*
  • Biopterins / metabolism
  • Coenzymes / metabolism
  • Escherichia coli / metabolism
  • Gene Expression
  • Half-Life
  • Humans
  • Mutation, Missense
  • Phenylalanine Hydroxylase / chemistry
  • Phenylalanine Hydroxylase / genetics*
  • Phenylalanine Hydroxylase / metabolism*
  • Phenylketonurias / genetics*
  • Phenylketonurias / metabolism
  • Point Mutation
  • Protein Binding
  • Protein Conformation
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / metabolism


  • Coenzymes
  • Recombinant Fusion Proteins
  • Biopterins
  • Phenylalanine Hydroxylase
  • sapropterin