Abstract
Phenylalanine hydroxylase [phenylalanine 4-monooxygenase; EC 1.14.16.1; L-phenylalanine, tetrahydropteridine:oxygen oxidoreductase(4-hydroxylating)] isolated from rat liver is a phosphoprotein containing approximately 0.31 mumol of protein-bound phosphate per mumol of subunit (50,000 molecular weight). When the enzyme is further phosphorylated in the presence of ATP and a 3'5'-cyclic-AMP-dependent protein kinase (EC 2.7.1.37; ATP:protein phsophotransferase), an additional 0.7 mumol of phosphate per mumol of subunit is introduced, bringing the total phosphate content up to about 1 mumol/mumol of subunit. This phosphorylation of the enzyme in vitro is accompanied by a 2.6-fold increase in hydroxylase activity when the activity is assayed in the presence of tetrahydrobiopterin. Partial proteolytic digestion of phenylalanine hydroxylase, which previously had been shown to activate the enzyme 20- to 50-fold [Fisher, D.B. & Kaufman, S. (1973) J. Biol. Chem. 248, 4345-4353], removes almost all of the phosphate from the enzyme.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Barranger J. A., Geiger P. J., Huzino A., Bessman S. P. Isozymes of phenylalanine hydroxylase. Science. 1972 Feb 25;175(4024):903–905. doi: 10.1126/science.175.4024.903. [DOI] [PubMed] [Google Scholar]
- Bergström G., Ekman P., Dahlqvist U., Humble E., Engström L. Subtilisin-catalyzed removal of phosphorylated site of pig liver pyruvate kinase without inactivation of the enzyme. FEBS Lett. 1975 Aug 15;56(2):288–291. doi: 10.1016/0014-5793(75)81111-2. [DOI] [PubMed] [Google Scholar]
- FISCHER E. H., GRAVES D. J., CRITTENDEN E. R. S., KREBS E. G. Structure of the site phosphorylated in the phosphorylase b to a reaction. J Biol Chem. 1959 Jul;234(7):1698–1704. [PubMed] [Google Scholar]
- Fisher D. B., Kaufman S. The stimulation of rat liver phenylalanine hydroxylase by lysolecithin and -chymotrypsin. J Biol Chem. 1973 Jun 25;248(12):4345–4353. [PubMed] [Google Scholar]
- Gilman A. G. A protein binding assay for adenosine 3':5'-cyclic monophosphate. Proc Natl Acad Sci U S A. 1970 Sep;67(1):305–312. doi: 10.1073/pnas.67.1.305. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Huang K. P., Cabib E. Yeast glycogen synthetase in the glucose 6-phosphate-dependent form. II. The effect of proteolysis. J Biol Chem. 1974 Jun 25;249(12):3858–3861. [PubMed] [Google Scholar]
- Huston R. B., Krebs E. G. Activation of skeletal muscle phosphorylase kinase by Ca2+. II. Identification of the kinase activating factor as a proteolytic enzyme. Biochemistry. 1968 Jun;7(6):2116–2122. doi: 10.1021/bi00846a014. [DOI] [PubMed] [Google Scholar]
- Kaufman S., Fisher D. B. Purification and some physical properties of phenylalanine hydroxylase from rat liver. J Biol Chem. 1970 Sep 25;245(18):4745–4750. [PubMed] [Google Scholar]
- Kaufman S. The phenylalanine hydroxylating system from mammalian liver. Adv Enzymol Relat Areas Mol Biol. 1971;35:245–319. doi: 10.1002/9780470122808.ch6. [DOI] [PubMed] [Google Scholar]
- Lloyd T., Kaufman S. Evidence for the lack of direct phosphorylation of bovine caudate tyrosine hydroxylase following activation by exposure to enzymatic phosphorylating conditions. Biochem Biophys Res Commun. 1975 Oct 6;66(3):907–917. doi: 10.1016/0006-291x(75)90726-3. [DOI] [PubMed] [Google Scholar]
- Milstien S., Kaufman S. Studies on the phenylalanine hydroxylase system in liver slices. J Biol Chem. 1975 Jun 25;250(12):4777–4781. [PubMed] [Google Scholar]
- Nimmo H. G., Cohen P. Glycogen synthetase kinase 2 (GSK 2); the identification of a new protein kinase in skeletal muscle. FEBS Lett. 1974 Oct 1;47(1):162–166. doi: 10.1016/0014-5793(74)80450-3. [DOI] [PubMed] [Google Scholar]