Related Experiment Video
Updated: Jul 27, 2026

Thermostabilization, Expression, Purification, and Crystallization of the Human Serotonin Transporter Bound to S-citalopram
Published on: November 27, 2016
Tryptophan is a precursor for melatonin and serotonin biosynthesis in in vitro regenerated St. John's wort (Hypericum
S J Murch1, S KrishnaRaj1, P K Saxena1
1Department of Plant Agriculture, Biotechnology Division, Edmund C. Bovey Complex, University of Guelph, Guelph, Ontario, Canada, N1G 2W1 Fax: +1-519-7670755 e-mail psaxena@uoguelph.ca, , , , , , CA.
Abstract:
HYPERICUM PERFORATUM: cv. Anthos) is presented. Isotope tracer experiments were performed on plantlets regenerated from thidiazuron-induced stem explants and grown on MS basal medium for 2 months. Radiolabel from 14C-tryptophan was recovered as 14C-indoleacetic acid, 14C-tryptamine, 14C-5-hydroxytryptophan, 14C-serotonin and 14C-melatonin in the treated St. John's wort plantlets. Chromatographic peak identity was confirmed by high performance liquid chromatography-mass spectrometry-mass spectrometry and quantification of melatonin by radioimmunoassay. Significantly more radiolabel was recovered in serotonin relative to melatonin under low light conditions with this ratio being reversed under increased lighting, indicating that the rate of flow through this biosynthetic pathway is regulated, at least in part, by light.
More Related Videos
09:31PCR Mutagenesis, Cloning, Expression, Fast Protein Purification Protocols and Crystallization of the Wild Type and Mutant Forms of Tryptophan Synthase
Published on: September 26, 2020
08:33Radiosynthesis of 1-(2-[18F]Fluoroethyl)-L-Tryptophan using a One-pot, Two-step Protocol
Published on: September 21, 2021
Related Concept Videos
Photoreceptors and Plant Responses to Light
Biological Clocks and Seasonal Responses
Photoreceptors and Visual Pathways
Amino Acid Biosynthetic Pathways
Repressible Operon: trp Operon
Production of Pharmaceuticals