Effect of diet on choline phosphotransferase, phosphatidylethanolamine methyltransferase and phosphatidyldimethylethanolamine methyltransferase in liver microsomes

Lipids ◽  
1980 ◽  
Vol 15 (6) ◽  
pp. 439-446 ◽  
Author(s):  
Dennis R. Hoffman ◽  
Eric O. Uthus ◽  
W. E. Cornatzer
Keyword(s):  
Liver Microsomes ◽  
Choline Phosphotransferase ◽  
Phosphatidylethanolamine Methyltransferase

Effects of a methyl-deficient diet on rat liver phosphatidylcholine biosynthesis

1981 ◽  
Vol 59 (7) ◽  
pp. 543-550 ◽  
Author(s):  
Dennis R. Hoffman ◽  
Judy A. Haning ◽  
W. E. Cornatzer
Keyword(s):  
Basal Diet ◽  
Female Rats ◽  
Deficient Diet ◽  
Acid Diet ◽  
Phosphatidylcholine Biosynthesis ◽  
Methionine Deficiency ◽  
Choline Phosphotransferase ◽  
Phosphatidylethanolamine Methyltransferase

To produce a severe choline–methionine deficiency, a synthetic L-amino acid diet, free of choline, methionine, vitamin B12, and folic acid and supplemented with guanidoacetic acid, a methyl group acceptor, was fed to female rats for 2 weeks. The in vitro activity of liver microsomal phosphatidylethanolamine methyltransferase was stimulated twofold when compared with basal diet controls. The activity of choline phosphotransferase was depressed by 86%; thus, the contribution of the methyltransferase in the overall synthesis of phosphatidylcholine apparently increased. However, measurement of the in vivo methylation of phosphatidylethanolamine by incorporation of [1,2-14C]ethanolamine into phosphatidylcholine indicates that the methylation pathway is markedly depressed in methyl deficiency. Hepatic concentrations of the methyltransferase substrate, S-adenosylmethionine, and the inhibitory metabolite, S-adenosylhomocysteine, were significantly altered such that an unfavorable environment for methylation was present in the deficient animal. The ratio of substrate to inhibitor was depressed from 5.2:1 in the controls to 1.7:1 in the livers of methyl-depleted rats. Control of transmethylation in accordance with the availability of substrates, phosphatidylethanolamine, or S-adenosylmethionine, and the level of S-adenosylhomocysteine is discussed.

Deactivation of anti-cancer drug letrozole to a carbinol metabolite by polymorphic cytochrome P450 2A6 in human liver microsomes

Xenobiotica ◽  
2009 ◽  
Vol 00 (00) ◽  
pp. 090901052053001-8
Author(s):  
K. Murai ◽  
H. Yamazaki ◽  
K. Nakagawa ◽  
R. Kawai ◽  
T. Kamataki
Keyword(s):  
Cytochrome P450 ◽  
Human Liver ◽  
Liver Microsomes ◽  
Human Liver Microsomes ◽  
Cancer Drug ◽  
Anti Cancer ◽  
Cytochrome P450 2A6

Selegiline Metabolism and Cytochrome P450 Enzymes:In vitro Study in Human Liver Microsomes*

2000 ◽  
Vol 86 (5) ◽  
pp. 215-221 ◽  
Author(s):  
Paivi Taavitsainen ◽  
Markku Anttila ◽  
Leena Nyman ◽  
Hari Karnani ◽  
Jarmo S. Salonen ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Human Liver ◽  
Liver Microsomes ◽  
Human Liver Microsomes ◽  
Vitro Study
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