ExplorEnz: EC 4.2.1.96

Your query returned 1 entry. Printable version

4.2.1.96

Accepted name:

4a-hydroxytetrahydrobiopterin dehydratase

Reaction:

4a-hydroxytetrahydrobiopterin = 6,7-dihydrobiopterin + H₂O

For diagram of biopterin biosynthesis, click here

Glossary:

4a-hydroxytetrahydrobiopterin = 6-[(1R,2S)-1,2-dihydroxypropyl]-5,6,7,8-tetrahydro-4a-hydroxypterin
6,7-dihydrobiopterin = 6-[(1R,2S)-1,2-dihydroxypropyl]-6,7-dihydropterin

Other name(s):

4α-hydroxy-tetrahydropterin dehydratase; 4a-carbinolamine dehydratase; pterin-4α-carbinolamine dehydratase; 4a-hydroxytetrahydrobiopterin hydro-lyase

Systematic name:

4a-hydroxytetrahydrobiopterin hydro-lyase (6,7-dihydrobiopterin-forming)

Comments:

In concert with EC 1.5.1.34, 6,7-dihydropteridine reductase, the enzyme recycles 4a-hydroxytetrahydrobiopterin back to tetrahydrobiopterin, a cosubstrate for several enzymes, including aromatic amino acid hydroxylases. The enzyme is bifunctional, and also acts as a dimerization cofactor of hepatocyte nuclear factor-1α (HNF-1).

Links to other databases:

BRENDA, EXPASY, Gene, KEGG, MetaCyc, PDB, CAS registry number: 87683-70-3

References:

1.	Citron, B.A., Davis, M.D., Milstien, S., Gutierrez, J., Mendel, D.B., Crabtree, G.R. and Kaufman, S. Identity of 4a-carbinolamine dehydratase, a component of the phenylalanine hydroxylation system, and DCoH, a transregulator of homeodomain proteins. Proc. Natl. Acad. Sci. USA 89 (1992) 11891–11894. [PMID: 1465414]
2.	Hauer, C.R., Rebrin, I., Thöny, B., Neuheiser, F., Curtius, H.C., Hunziker, P., Blau, N., Ghisla, S., Heizmann, C.W. Phenylalanine hydroxylase-stimulating protein: pterin-4α-carbinolamine dehydratase from rat and human liver. J. Biol. Chem. 268 (1993) 4828–4831. [PMID: 8444860]
3.	Thony, B., Neuheiser, F., Blau, N. and Heizmann, C.W. Characterization of the human PCBD gene encoding the bifunctional protein pterin-4 α-carbinolamine dehydratase/dimerization cofactor for the transcription factor HNF-1 α. Biochem. Biophys. Res. Commun. 210 (1995) 966–973. [PMID: 7763270]
4.	Endrizzi, J.A., Cronk, J.D., Wang, W., Crabtree, G.R. and Alber, T. Crystal structure of DCoH, a bifunctional, protein-binding transcriptional coactivator. Science 268 (1995) 556–559. [PMID: 7725101]
5.	Cronk, J.D., Endrizzi, J.A. and Alber, T. High-resolution structures of the bifunctional enzyme and transcriptional coactivator DCoH and its complex with a product analogue. Protein Sci. 5 (1996) 1963–1972. [PMID: 8897596]

[EC 4.2.1.96 created 1999, modified 2020]