title: Evidence for the existence of protein inhibitors for S-adenosyl-L-methionine-mediated methylation of phosphatidylethanolamine in rat liver cytosol.
abstract: The effect of rat liver cytosol on phosphatidylcholine biosynthesis via the N-methylation of phosphatidylethanolamine has been studied. The purified rat liver plasma membrane was used as an enzyme source. The rat liver 105,000 x g supernatant(cytosol) contained two different inhibitors for S-adenosyl-L-methionine-mediated methylation of phosphatidylethanolamine to phosphatidyl-N-mono-methylethanolamine. The inhibitors were inactivated by pretreatment with trypsin or heating at 96 degrees C, but were not inactivated by RNase. The inhibitors did not inhibit the synthesis of phosphatidylcholine from phosphatidyl-N-mono-methylethanolamine. The results indicate that two different protein inhibitors for methylation are present in rat liver cytosol fraction and that the inhibition by these proteins may have a role for the regulation of phosphatidylcholine synthesis in the plasma membrane.
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000201:enzymology; D003600:Cytosol / Q000201:enzymology*; D066298:In Vitro Techniques; D008099:Liver / Q000201:enzymology*; D008297:Male; D008745:Methylation; D008862:Microsomes, Liver / Q000201:enzymology; D008930:Mitochondria, Liver / Q000201:enzymology; D010713:Phosphatidylcholines / Q000096:biosynthesis; D010714:Phosphatidylethanolamines / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012436:S-Adenosylmethionine / Q000037:antagonists & inhibitors* / Q000502:physiology
chemical_list: D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D012436:S-Adenosylmethionine