Abstract
The tetrahydropterin-dependent aromatic amino acid hydroxylases phenylalanine hydroxylase (PheH) and tyrosine hydroxylase (TyrH) are 75% identical in their 335 C-terminal amino acid residues (1). Deletion mutagenesis and proteolysis of the native enzymes have shown that these amino acids contain the residues responsible for catalysis (2–6). Despite these extensive identities, these enzymes differ in their substrate specificities. PheH is very specific for phenylalanine; although it can hydroxylate tryptophan to a small extent, it is unable to hydroxylate tyrosine (7,8). TyrH is able to hydroxylate phenylalanine with approximately 66% the Vmax value with tyrosine (9,10). These substrate specificities are determined by the C domains (11). The goal of the experiments described here was to identify amino acid residues responsible for these different specificities.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Grenett, H.E., Ledley, F.D., Reed, L.L., Woo, S.L.C. Full-length cDNA for rabbit tryptophan hydroxylase: Functional domains and evolution of aromatic amino acid hydroxylases. Proc. Natl. Acad. Sci. USA 84: 5530–5534, 1987.
Abate, C., Joh, T.H. Limited proteolysis of rat brain tyrosine hydroxylase defines an N-terminal region required for regulation of cofactor binding and directing substrate specificity. J. Mol. Neurosci. 2: 203–215, 1991.
Daubner, S.C., Lohse, D.L., Fitzpatrick, P.F. Expression and characterization of catalytic and regulatory domains of rat tyrosine hydroxylase. Prot. Sci. 2: 1452–1460, 1993.
Abita, J.-P., Parniak, M., Kaufman, S. The activation of rat liver phenylalanine hydroxylase by limited proteolysis, lysolecithin, and tocopherol phosphate. Changes in conformation and catalytic properties. J. Biol. Chem. 259: 14560–14566, 1984.
D’Sa, C., Arthur, R. Jr., Kuhn, D.M. Expression and deletion mutagenesis of rat tryptophan hydroxylase fusion proteins: Delineation of the enzyme catalytic core. J. Neurochem. 67: 917–926, 1996.
Moran, G.R., Daubner, S.C., Fitzpatrick, P.F. Expression and characterization of the catalytic core of tryptophan hydroxylase. J. Biol. Chem. 273: 12259–12266, 1998.
Fisher, D.B., Kaufman, S. Tetrahydropterin oxidation without hydroxylation catalyzed by rat liver phenylalanine hydroxylase. J. Biol. Chem. 248: 4300–4304, 1973.
Davis, M.D., Kaufman, S. Products of the tyrosine-dependent oxidation of etrahydrobiopterin by rat liver phenylalanine hydroxylase. Arch. Biochem. Biophys. 304: 9–16, 1993.
Hillas, P.J., Fitzpatrick, P.F. A mechanism for hydroxylation by tyrosine hydroxylase based on partitioning of substituted phenylalanines. Biochemistry 35: 6969–6975, 1996.
Fitzpatrick, P.F. Studies of the rate-limiting step in the tyrosine hydroxylase reaction: Alternate substrates, solvent isotope effects, and transition state analogs. Biochemistry 30: 6386–6391, 1991.
Daubner, S.C., Hillas, P. J., Fitzpatrick, P.F. Characterization of chimeric pterin dependent hydroxylases: Contributions of the regulatory domains of tyrosine and phenylalanine hydroxylase to substrate specificity. Biochemistry 36: 11574–11582, 1997.
Davis, M.D., Kaufman, S. The tyrosine-dependent oxidation of tetrahydropterins by lysolecithin-activated rat liver phenylalanine hydroxylase. J. Biol. Chem. 263: 17312–17316, 1988.
Xia, T., Gray, D.W., Shiman, R. Regulation of rat liver phenylalanine hydroxylase. III. Control of catalysis by (6R)-tetrahydrobiopterin and phenylalanine. J. Biol. Chem.269: 24657–24665, 1994.
Kaufman S. “Regulation of the aromatic amino acid hydroxylases.” In Chemistry and biology of pteridines 1989, H.-Ch. Curtius, S. Ghisia, N. Blau, eds., Walter de Gruyter & Co., New York, pp. 601–611, 1991.
Author information
Authors and Affiliations
Editor information
Rights and permissions
Copyright information
© 2002 Springer Science+Business Media New York
About this chapter
Cite this chapter
Daubner, S.C., Melendez, J., Fitzpatrick, P.F. (2002). Substrate Specificities of Phenylalanine and Tyrosine Hydroxylase: Role of Aspartate 425 of Tyrosine Hydroxylase. In: Milstien, S., Kapatos, G., Levine, R.A., Shane, B. (eds) Chemistry and Biology of Pteridines and Folates. Springer, Boston, MA. https://doi.org/10.1007/978-1-4615-0945-5_21
Download citation
DOI: https://doi.org/10.1007/978-1-4615-0945-5_21
Publisher Name: Springer, Boston, MA
Print ISBN: 978-1-4613-5317-1
Online ISBN: 978-1-4615-0945-5
eBook Packages: Springer Book Archive