Purification and properties of phosphatidyl-N-monomethylethanolamine N-methyltransferase, the enzyme catalyzing the second and the third steps in the phosphatidylethanolamine N-methyltransferase system, from mouse liver microsomes.
The phosphatidylethanolamine (PE) N-methyltransferase (MT) system is known to convert PE to phosphatidylcholine by three successive N-methylations. Phosphatidyl-N-monomethylethanolamine (PME) MT was purified 1,400-fold from mouse liver microsomes and separated from the PE-MT activity for the first time. This enzyme catalyzes N-methylations of PME and phosphatidyl-N,N-dimethylethanolamine, the intermediates of PE-MT system, but not PE, the initial substrate of the PE-MT system. In addition, a preparation with a different affinity to S-adenosyl-L-homocysteine catalyzing all the three methylations was obtained. These results suggest that at least two enzymes are involved in the PE-MT system.
Tanaka
Y
Y
Department of Chemistry, National Institute of Health, Tokyo, Japan.
Amano
F
F
Maeda
M
M
Nishijima
M
M
Akamatsu
Y
Y
D000818:Animals; D004492:Edetic Acid / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D015636:Magnesium Chloride / Q000494:pharmacology; D008297:Male; D008745:Methylation; D008780:Methyltransferases / Q000302:isolation & purification* / Q000378:metabolism; D051379:Mice; D008862:Microsomes, Liver / Q000378:metabolism; D050941:Phosphatidyl-N-Methylethanolamine N-Methyltransferase; D010713:Phosphatidylcholines / Q000378:metabolism; D050918:Phosphatidylethanolamine N-Methyltransferase; D010714:Phosphatidylethanolamines / Q000378:metabolism; D013379:Substrate Specificity
D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; C032000:phosphatidyl-N-monomethylaminoethanol; D015636:Magnesium Chloride; D004492:Edetic Acid; D008780:Methyltransferases; D050918:Phosphatidylethanolamine N-Methyltransferase; D050941:Phosphatidyl-N-Methylethanolamine N-Methyltransferase