title: Heavy and light forms of some aminoacyl-tRNA synthetases in fraction X, microsomes and cytosol of rabbit liver.
abstract: Aminoacyl-tRNA synthetase activity for alanine, glutamic acid, lysine and phenylalanine was studied in the three subcellular fractions of rabbit liver: fraction X, microsomes and cytosol. From 60 to 80% of the enzyme activities were found in fraction X and microsomes. Fraction X was especially rich in the synthetase activities. By means of gel chromatography, heavy (over 10(6) daltons) and light (below 480 X 10(3) daltons) forms of lysyl- and phenylalanyl- but only light ones of alanyl- and glutamyl-tRNA synthetase activities were found in all the subcellular fractions studied. It is concluded that in higher organisms (mammals) all aminoacyl-tRNA synthetases, at least in part, are associated with cell structural constituents.
mesh_terms: D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D000818:Animals; D003600:Cytosol / Q000201:enzymology; D008099:Liver / Q000201:enzymology* / Q000648:ultrastructure; D008862:Microsomes, Liver / Q000201:enzymology; D008970:Molecular Weight; D011817:Rabbits; D013347:Subcellular Fractions / Q000201:enzymology
chemical_list: D000604:Amino Acyl-tRNA Synthetases