Open AccessOccurrence and Particle Character of Aminoacyl‐tRNA Synthetases in the Post‐Microsomal Fraction from Rat Liver
Author(s) -
Vennegoor Claudia,
Bloemendal Hans
Publication year - 1972
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1972.tb01788.x
Subject(s) - sephadex , microsome , centrifugation , chromatography , enzyme , biochemistry , size exclusion chromatography , isoelectric focusing , chemistry , biology , microbiology and biotechnology
A post‐microsomal fraction (Fraction X) was isolated from cell sap from rat liver by centri‐fugation at 105000 × g for 15 h. The activity of a number of aminoacyl‐tRNA synthetases was considerably higher in the resulting pellet than in the supernatant. These enzymes (glutaminyl‐, isoleucyl‐, leucyl‐, lysyl‐, and methionyl‐tRNA synthetase) were purified by gel filtration on Sephadex G‐200, chromatography on DEAE‐Sephadex A‐50 and on hydroxyapatite. As compared with crude cell sap a 120‐ to 170‐fold purification was achieved. In all purification steps, including additional centrifugation on sucrose gradients or isoelectric focusing, the major peak of activity of the five enzymes coincided. In the electron microscope circular and rectangular particles, 11–14 nm in size, could be visualized. From these findings we suggest that in rat liver cells, if not in all animal cells, part of the aminoacyl‐tRNA synthetases occur in a particulate state.