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Some aspects of the phosphorylation of phenylalanine 4-monooxygenase by a calcium-dependent and calmodulin-dependent protein kinase.
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- Additional Information
- Source:
Publisher: Blackwell Science Ltd. on behalf of the Federation of European Biochemical Societies Country of Publication: England NLM ID: 0107600 Publication Model: Print Cited Medium: Print ISSN: 0014-2956 (Print) Linking ISSN: 00142956 NLM ISO Abbreviation: Eur J Biochem Subsets: MEDLINE
- Publication Information:
Publication: -2004: Oxford, UK : Blackwell Science Ltd. on behalf of the Federation of European Biochemical Societies
Original Publication: Berlin, New York, Springer.
- Subject Terms:
- Abstract:
A calmodulin-dependent protein kinase purified from liver catalyzed the incorporation of up to 0.7 mol of phosphate per mol subunit of phenylalanine 4-monooxygenase. The phosphorylation was accompanied by a proportional increase in the hydroxylase activity. The reaction was Ca2+-dependent and was inhibited by physiological concentrations of phenylalanine. Phenylalanine 4-monooxygenase was also a substrate for the cGMP-dependent protein kinase, but in this system phenylalanine stimulated the rate of phosphorylation to a similar extent as that observed in the reaction catalyzed by cAMP-dependent protein kinase. The hydroxylase was not a substrate for phosphorylase kinase. The calmodulin-dependent reversal of the kinase reaction in the presence of MgADP, was also inhibited by phenylalanine. Since the kinetics of the reverse reaction was the same using 32P-hydroxylase phosphorylated by calmodulin-dependent and cAMP-dependent kinases, it is likely that both kinases phosphorylate the same site on the enzyme. This conclusion was further supported by peptide mapping of tryptic and peptic digests of 32P-hydroxylase, which revealed one major phosphopeptide with enzyme phosphorylated by either kinase. The Ca2+-dependent and calmodulin-dependent phosphorylation described above may mediate the increased phosphorylation of the hydroxylase [Garrison, J. C., Johnsen, D. E., and Campanile, C. P. (1984) J. Biol. Chem. 259, 3283-3292] and its increased activity [Fisher, M. J., Santana, M. A., and Pogson, C. I. (1984) Biochem. J. 219, 87-90] recently observed in hepatocytes exposed to Ca2+-elevating agents.
- Grant Information:
AM 15988 United States AM NIADDK NIH HHS; AM 17808 United States AM NIADDK NIH HHS
- Accession Number:
0 (Calmodulin)
0 (Nucleotides, Cyclic)
47E5O17Y3R (Phenylalanine)
EC 1.14.16.1 (Phenylalanine Hydroxylase)
EC 2.7.- (Protein Kinases)
SY7Q814VUP (Calcium)
- Publication Date:
Date Created: 19841115 Date Completed: 19841220 Latest Revision: 20190620
- Publication Date:
20250114
- Accession Number:
10.1111/j.1432-1033.1984.tb08518.x
- Accession Number:
6489353
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