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Characterization of tryptamine 5-hydroxylase and serotonin synthesis in rice plants
- Source :
- Plant Cell Reports. 26:2009-2015
- Publication Year :
- 2007
- Publisher :
- Springer Science and Business Media LLC, 2007.
-
Abstract
- Serotonin is a well-known pineal hormone that in mammals plays a key role in mood. In plants, serotonin is implicated in several physiological roles such as flowering, morphogenesis, and adaptation to environmental changes. However, its biosynthetic enzyme in plants has not been characterized. Therefore, we measured the serotonin content and enzyme activity responsible for serotonin biosynthesis in rice seedlings. Tryptamine 5-hydroxylase (T5H), which converts tryptamine into serotonin, was found as a soluble enzyme that had maximal activity in the roots. The maximal activity of T5H was closely associated with the enriched synthesis of serotonin in roots. Tetrahydropterine-dependent T5H activity was inhibited by tyramine, tryptophan, 5-OH-tryptophan, and octopamine, but remained unaltered by dopamine in vitro. The tissues of rice seedlings grown in the presence of tryptamine exhibited a dose-dependent increase in serotonin in parallel with enhanced T5H enzyme activity. However, no significant increase in serotonin was observed in rice tissues grown in the presence of tryptophan, suggesting that tryptamine is a bottleneck intermediate substrate for serotonin synthesis.
- Subjects :
- Tryptamine
Serotonin
medicine.medical_specialty
Dopamine
Tyramine
Plant Science
Biology
Plant Roots
Mixed Function Oxygenases
Enzyme activator
chemistry.chemical_compound
Cytochrome P-450 Enzyme System
Internal medicine
medicine
Octopamine
Tryptophan
food and beverages
Oryza
General Medicine
Tryptamines
Enzyme assay
Enzyme Activation
Endocrinology
Biochemistry
chemistry
biology.protein
Octopamine (neurotransmitter)
Agronomy and Crop Science
medicine.drug
Subjects
Details
- ISSN :
- 1432203X and 07217714
- Volume :
- 26
- Database :
- OpenAIRE
- Journal :
- Plant Cell Reports
- Accession number :
- edsair.doi.dedup.....f689b3336fc2b5dd6de2eeb6a53aa30d