Biopolymers and cell. 1995; 11 (6): 69-74

The effects of myocardial ischemia on the aggregate state of rabbit liver aminoacyl-tRNA synthetases and tRNA methyltransferases

VIEZELIENE D. V., TARASEVICIENE L. E., IVANOV L. L., JASAITIS A. A., LUKOSEVICIUS L. J.

The activities of aminoacyl-lRNA synthetases and tRNA methyltransferases in postribosomal extracts from normal rabbit liver and 12 hr after experimental myocardial ischemia (EMI), as well as their distribution between high-molecular-mass complexes and free enzymes fractions, have been compared. An increase in the activity of glutamyl-, glycyl-, leucyl-, lysyl- and seryl-tRNA synthetases by 12—44 % has been determined under EMI. The total tRNA methyltransferase activity is increased up to 47 %. In the case of EMI among the methylated products of submethylated tRNA the contents of m1A, m5C, m 5U, O-m-R are decreased, and the content of m7G is increased Gel chromatography of the postribosomal extract on a Sephadex G-200 column shows that aminoacyl-tRNA synthetase and tRNA-methyltransferase activities are distributed between the high-molecular-mass complex (Mr > > 1*106 Daltons) and fractions of lower molecular mass complexes and free enzymes. In the of EMI aminoacyl-tRNA synthetase and tRNA methyltransferase activiteis are partly redistributed from the high-molecular-mass complex into th elowel molecular mass fraction, what may be related to the alteration of protein biosynthesis in liver under myocardial ischemia