title: Synthesis and degradation of methylated proteins of mouse organs: correlation with protein synthesis and degradation.
abstract: L-(Methyl-14C)-methionine was administered i.p. to mice, and the incorporation of radioactive methionine into proteins and methyllysine and methylarginine residues formed by the transfer of the methyl-14C group of methionine were measured. Tissue protein was actively methylated in organs having a high activity of protein synthesis, and the in vivo methylating activity in organs was not correlated with theprotein methylating activity of the organs determined in vitro. Puromycin inhibited both protein synthesis and protein methylation in mouse organs to a similar degree. Neither the formation of S-adenosyl-(methyl-14C)-methionine nor protein methylase was inhibited by puromycin. The data suggests that proteins are methylated immediately after protein synthesis, that is, newly synthesized proteins are the substrates of protein methylation. Radioactive methionine and the [C14] methyl groups of methyllysine and methylarginine residues of tissue proteins are degraded in parallel over a period of 3 wk, suggesting that protein methylation is an irreversible type of protein modification.
mesh_terms: D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000378:metabolism; D001921:Brain / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008239:Lysine / Q000031:analogs & derivatives / Q000378:metabolism; D008297:Male; D008715:Methionine / Q000378:metabolism*; D008745:Methylation; D008780:Methyltransferases / Q000378:metabolism; D051379:Mice; D014176:Protein Biosynthesis; D011506:Proteins / Q000378:metabolism*; D011691:Puromycin / Q000494:pharmacology; D013154:Spleen / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism
chemical_list: D011506:Proteins; D011691:Puromycin; D001120:Arginine; D008715:Methionine; D008780:Methyltransferases; D008239:Lysine