Journal ArticleDOI
Identification of alkaloids; the condensation products of biogenic amines with formaldehyde, enzymatically formed from 5-methyltetrahydrofolic acid.
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The alkaloids have been shown to originate from a spontaneous condensation of the corresponding amines with formaldehyde, this latter being formed in the first stage of the reaction by enzymatic conversion from 5-methyltetrahydrofolic acid.Abstract:
The use of thin-layer chromatography has demonstrated that incubations of indoleamines with 5-methyl[14-C]tetrahydrofolic acid and an enzyme previously described as an N-methyltransferase, do not yield Nw, N1, or O-methylated products. Further elucidation by thin-layer chromatography, gas chromatography, mass spectrometry and selected ion monitoring enabled us to identify the reaction products as tetrahydroisoquinolines and tetrahydro-beta-carbolines in mixtures incubated respectively with catecholamines and indoleamines in the presence of 5-methyl[14-C]tetrahydrofolic acid and enzyme. The alkaloids have been shown to originate from a spontaneous condensation of the corresponding amines with formaldehyde, this latter being formed in the first stage of the reaction by enzymatic conversion from 5-methyltetrahydrofolic acid.read more
Citations
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Journal ArticleDOI
The simple β-carboline alkaloids
James R.F. Allen,Bo Holmstedt +1 more
TL;DR: The simple β-carbolines are presented as a distinct group of alkaloids displaying structural modification of three basic ring systems and aspects of their metabolism, pharmacological properties and taxonomic significance are briefly summarized.
Journal ArticleDOI
Protective Actions of the Vesicular Monoamine Transporter 2 (VMAT2) in Monoaminergic Neurons
Thomas S. Guillot,Gary W. Miller +1 more
TL;DR: VMAT2 provides neuroprotection from both endogenous and exogenous toxicants and that while VMAT2 has been adapted by eukaryotes for synaptic transmission, it is derived from phylogenetically ancient proteins that originally evolved for the purpose of cellular protection.
Journal ArticleDOI
Neurobiology of tetrahydro-β-carbolines
TL;DR: Evidence for the formation of THβC's as well as their neurochemical, neuroendocrinological, and behavioral effects is described in this review.
Journal ArticleDOI
Tetrahydronorharmane (Tetrahydro-β-carboline), a physiologically occurring compound of indole metabolism
TL;DR: A sensitive method is described to measure tetrahydronorharmane in the urine of man and rats as well as in the forebrain of rats, demonstrating the existence of THN and the hypothesis that THN acts as a compound modulating neuronal mechanism.
Journal ArticleDOI
Presence of methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinolines, derivatives of the neurotoxin isoquinoline, in parkinsonian lumbar CSF.
TL;DR: The TIQ derivatives 2-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline and 1-MDTIQ were identified for the first time as possible endogenous neurotoxins in parkinsonian but not in normal human lumbar cerebrospinal fluid by high performance liquid chromatography with electrochemical detection.
References
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Journal ArticleDOI
Tetrahydroisoquinoline alkaloids: in vivo metabolites of L-dopa in man.
TL;DR: Tetrahydroisoquinoline alkaloids have been unequivocally demonstrated in vivo for the first time in parkinsonian patients on L-dopa treatment and may have a profound bearing on how L- dopa acts.
Journal ArticleDOI
Zur Frage der Biogenese der Isochinolin‐alkaloide. Die Synthese des 1‐Methyl‐6,7‐dioxy‐1,2,3,4‐tetrahydro‐isochinolins unter physiologischen Bedingungen
Clemens Schöpf,Hans Bayerle +1 more
Journal ArticleDOI
Methyltetrahydrofolic acid mediates N- and O-methylation of biogenic amines.
TL;DR: With methyltetrahydrofolic acid, serotonin is O-methylated to 5-methoxytryptamine, a novel indoleamine in mammalian brain.
Journal ArticleDOI
N-Methylation of Dopamine to Epinine in Brain Tissue using N-Methyltetrahydrofolic Acid as the Methyl Donor
TL;DR: In this model epinine should be considered as the immediate precursor of adrenaline2, and in this model a simplified model more compatible with the concept of intracellular compartments is proposed.
Journal ArticleDOI
Multiple N-methytransferases for aromatic alkylamines in brain
Louise L. Hsu,Arnold J. Mandell +1 more
TL;DR: Assays in the presence of each donor in combination with each substrate suggested the possible existence of multiple N-methyltransferases, with one specific for tryptamine and the others non-specific for aromatic alkylamines.
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Enzymatic formation of tetrahydro-beta-carboline from tryptamine and 5-methyltetrahydrofolic acid in rat brain fractions: regional and subcellular distribution.
L. L. Hsu,Arnold J. Mandell +1 more