Advertisement

Tryptophan Hydroxylase Activity in Serotonin Producing Mast Cells

Dependence on Intracellular Iron Concentration Manipulated by Permeable Chelators
  • H. Hasegawa
  • Y. Iida
  • K. Oguro
  • M. Kojima
  • A. Ichiyama
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 398)

Abstract

The monoamine, serotonin, has long been known to function as a hormone, neurotransmitter, and local chemical mediator. Enterochromaffin cells of gastrointestinal mucosa are believed to be the predominant source in the periphery and, in rodents, mast cells are also a source. Tryptophan hydroxylase (TPH) is the rate limiting enzyme in the biosynthesis of this monoamine. TPH of peripheral origin and brain TPH are known to differ with respect to their various properties (Nakata and Fujisawa, 1982; Hasegawa et al., 1987; Kim et al., 1991). The phosphorylated brain enzyme is known to be activated in the presence of 14-3-3 protein (Yamauchi et al., 1981), however, little is known concerning regulation of the enzyme of peripheral origin such as from mast cells and gastrointestinal enterochromaffin cells. In vitro activation of peripheral TPH by anaerobic incubation with DTT and Fe2+ included in routine measurement of this enzyme since the enzyme is very labile and must be re-activated prior to the assay (Ichiyama et al., 1974). With regard to the mechanism of activation, accumulated data from in vitro studies suggest that this activation requires supplementation with ferrous iron. Hence “DTT-activation” of the enzyme could be termed “ferrous iron activation”. Some degree of uncertainty has remained regarding whether the iron concentration in the living cells is inadequate for TPH activation. The question arose as to whether the intracellular enzyme is actually supplied with sufficient ferrous iron or even whether “ferrous iron activation” really occurs. The aim of this work was to answer this question. Intracellular enzyme active was assessed under conditions in which the iron concentration was manipulated using permeable chelators. Mouse bone marrow derived mast cells (BMMC) in culture were generally used in this work as a source of natural mast cells.

Keywords

Mast Cell Ferrous Iron Mouse Bone Marrow Tryptophan Hydroxylase RBL2H3 Cell 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Reference

  1. Hasegawa H., Yanagisawa M., Inoue F., Yanaihara N., and Ichiyama A., 1987, Demonstration of non-neural tryptophan 5-mono-oxygenase in mouse intestinal mucosa, Biochem J.248: 501.Google Scholar
  2. Ichiyama A., Hori S., Mashimo Y., Nukiwa T., and Makuuchi H., 1974, The activation of bovine pineal tryptophan 5-monooxygenase, FEBS Lett40: 88.CrossRefGoogle Scholar
  3. Kim K.S., Wessel T.C., Stone D.M., Carver C.H., Joh T.H., and Park D.H., 1991, Molecular cloning and characterization of cDNA encoding tryptophan hydroxylase from rat central serotonergic neurons, Brain Res Mol Brain Res9: 277.Google Scholar
  4. Nagatsu T., Sawada M., and Yamaguchi T., 1983, Tryptophan hydroxylase system in brain tissue slices assayed by hight-performance liquid chromatography, Neurochem Int.5: 603.CrossRefGoogle Scholar
  5. Nakata H., and Fujisawa H., 1982, Tryptophan 5-monooxygenase from mouse mastocytoma P815. A simple purification and general properties, Eur J Biochem124: 595.CrossRefGoogle Scholar
  6. Rouault T., Rao K., Harford J., Mattia E., and Klausner R.D., 1985, Hemin, chelatable iron, and the regulation of transferrin receptor biosynthesis, J Biol Chem260: 14862.Google Scholar
  7. Yamauchi T., Nakata H., and Fujisawa H., 1981, A new activator protein that activates tryptophan 5-monooxy- genase and tyrosine 3-monooxygenase in the presence of Ca2+-, calmodulin-dependent protein kinase, J Biol Chem.256: 5405.Google Scholar

Copyright information

© Plenum Press, New York 1996

Authors and Affiliations

  • H. Hasegawa
    • 1
  • Y. Iida
    • 1
  • K. Oguro
    • 1
  • M. Kojima
    • 1
  • A. Ichiyama
    • 2
  1. 1.Department of BioscienceThe Nishi-Tokyo UniversityYamanashiJapan
  2. 2.Department of BiochemistryHamamatsu University School of MedicineHamamatsuJapan

Personalised recommendations