Metabolism of N-methyl, N-propargylphenylethylamine: studies with human liver microsomes and cDNA expressed cytochrome P450 (CYP) enzymes.
1. We used an in vitro screening procedure and studies with individual human liver microsomes and cDNA-expressed CYP enzymes to investigate the metabolism of the putative neuroprotective drug N-methyl,N-propargyl-2-phenylethylamine (MPPE) to N-methylphenylethylamine (N-methylPEA) and N-propargylphenylethylamine (N-propargylPEA). 2. An electron-capture gas chromatographic procedure previously developed in our laboratories was used to measure the quantities of N-methylPEA and N-propargylPEA formed in the experiments with a single donor human liver microsome panel and cDNA expressed single CYP enzyme systems. The data were fitted to nonlinear regressions using Prism to determine kinetic constants. The results from a fluorogenic screen determined which cDNA-expressed single CYP enzymes were investigated. 3. CYP2B6, CYP2C19, and CYP2D6 all contributed to the formation of N-methylPEA, while only CYP2B6 catalyzed the formation of N-propargylPEA. The K (M) and V (max) values for N-propargylPEA formation were 290 +/- 70 microM and 139+/-16 ng/mL/min. The values for formation of N-methylPEA were not determined from these experiments due to the complexity of fitting the data to a three-variable equation, but data on the time course of N-methylPEA formation are presented. 4. Catabolism of MPPE to N-methylPEA and N-propargylPEA is catalyzed by CYP enzymes. CYP2B6, 2C19 and 2D6 all contribute to the depropargylation of the parent compound, but only CYP2B6 also catalyzes demethylation. CYP2C19 was found to be the most active with respect to generation of N-methylPEA.
Rittenbach
Katherine A
KA
Neurochemical Research Unit, Department of Psychiatry, University of Alberta, 1E7.31 Mackenzie Centre, Edmonton, Alberta, Canada.
Holt
Andrew
A
Ling
Lei
L
Shan
Jackie
J
Baker
Glen B
GB
D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics / Q000378:metabolism; D001667:Binding, Competitive; D065702:Cytochrome P-450 CYP2B6; D065731:Cytochrome P-450 CYP2C19; D019389:Cytochrome P-450 CYP2D6 / Q000235:genetics / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism*; D018076:DNA, Complementary; D004789:Enzyme Activation; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D066298:In Vitro Techniques; D008658:Inactivation, Metabolic; D008862:Microsomes, Liver / Q000201:enzymology*; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism; D018696:Neuroprotective Agents / Q000737:chemistry / Q000493:pharmacokinetics*; D010089:Oxidoreductases, N-Demethylating / Q000235:genetics / Q000378:metabolism; D012642:Selegiline / Q000031:analogs & derivatives* / Q000737:chemistry / Q000493:pharmacokinetics
D018076:DNA, Complementary; C508639:N-Methyl,N-propargyphenylethylamine; D018696:Neuroprotective Agents; D012642:Selegiline; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D001189:Aryl Hydrocarbon Hydroxylases; C585599:CYP2B6 protein, human; C045793:CYP2C19 protein, human; D065702:Cytochrome P-450 CYP2B6; D065731:Cytochrome P-450 CYP2C19; D019389:Cytochrome P-450 CYP2D6; D010089:Oxidoreductases, N-Demethylating