Related Experiment Video
Updated: Sep 4, 2026

Mass Spectrometry and Luminogenic-based Approaches to Characterize Phase I Metabolic Competency of In Vitro Cell Cultures
Published on: March 28, 2017
Tryptamine: a possible endogenous substrate for CYP2D6
C Martínez1, J A Agúndez, G Gervasini
1Department of Pharmacology, Medical School, University of Extremadura, Badajoz, Spain.
Abstract:
The fact that CYP2D6 is not only expressed in liver but also in brain and the clinical association of this cytochrome with Parkinson's disease suggests the possibility of existence of some endogenous substrate, and among these perhaps one or more neurotransmitters could be metabolized by CYP2D6. In this study we explored such a possibility by studying the modulation of CYP2D6 activity by several neurotransmitters. Our findings confirm the occurrence of a competitive inhibition of dextromethorphan O-demethylation in the presence of tryptamine, with a Ki value of 44.6 microM. Tryptamine was metabolized in human liver microsomes by an enzyme activity with a K(m) of 3.6 +/- 0.9 microM. Such activity is NADPH dependent and is inhibited by quinidine and CYP2D6-specific substrates. The product of the reaction is tryptophol. These results suggest that tryptamine may be an endogenous substrate of CYP2D6.
More Related Videos
10:38Simultaneous Quantification of Selected Kynurenines Analyzed by Liquid Chromatography-Mass Spectrometry in Medium Collected from Cancer Cell Cultures
Published on: May 9, 2020
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
Related Concept Videos
Drugs Affecting Neurotransmitter Release or Uptake
Drugs Affecting Neurotransmitter Synthesis
Antidepressant Drugs: MAOIs and Other Agents
Nonlinear Pharmacokinetics: Dependence of Elimination Half-Life and Dose Clearance
A study on guinea pigs examined the...
Pharmacogenetics of Phase I Enzymes: Cytochrome P450 Isozymes
Amino Acid Biosynthetic Pathways