title: [New studies on inhibition of tRNA N2 guanine methyltransferase by S-adenosyl-homocysteine and S-adenosyl-methionine analogs].
abstract: New structural analogs of S-adenosyl homocysteine (SAH) 1-9, 11-14, 19-21) and of S-adenosyl methionine (15-18) have been tested as inhibitors of a N-2 guanine methyltransferase extract from rabbit liver with E. coli B tRNA as substrate. The sulfonium compounds (mixture of +/- diastereoisomers) are more inhibitory than the sulfide derivatives but less inhibitory than SAH itself. The replacement of the aminoacid chain in SAH by various alphatic radicals leads to a correlation between their bulk and the size of the enzymatic site. The monosubstitution of N-6 amino group does not affect significantly the inhibitory effect, which is completely canceled by the disubstitution of N-6.
mesh_terms: D000818:Animals; D004926:Escherichia coli; D006147:Guanine / Q000378:metabolism; D006710:Homocysteine / Q000031:analogs & derivatives*; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D012343:RNA, Transfer / Q000378:metabolism; D011817:Rabbits; D012435:S-Adenosylhomocysteine / Q000031:analogs & derivatives* / Q000494:pharmacology; D012436:S-Adenosylmethionine / Q000031:analogs & derivatives* / Q000494:pharmacology; D012359:tRNA Methyltransferases / Q000378:metabolism*
chemical_list: D006710:Homocysteine; D006147:Guanine; D012436:S-Adenosylmethionine; D012343:RNA, Transfer; D012435:S-Adenosylhomocysteine; D012359:tRNA Methyltransferases
vernacular_title: Nouvelles études de l'inhibition d'une tRNA N2 guanine méthyltransférase par des analogues de la S-adénosyl-homocystéine et de la S-adénosyl-méthionine