[Effect of cultured Polyscias cells on the activity of components of the protein-synthesizing system of rabbit liver]. / Vliianie kul'tiviruemykh kletok polistsiasa na aktivnost' komponentov beloksinteziruiushchei sistemy pecheni krolikov.

The authors studied teh effect of cultured Polyscias filcifolia Bailey cells on protein biosynthesis in an acellular system obtained from the liver of rabbits in experimental myocardial ischemia. It was found that the preparation normalizes the values of protein biosynthesis, the duration of the average polypeptide chain synthesis, and the activity of aminoacyl-tRNA synthetases.

[Interaction of eukaryotic aminoacyl-tRNA-synthases with polyribosomes]. / Izuchenie vzaimodeistviia éukarioticheskikh aminoatsil-tRNK-sintetaz s poliribosomami.

Properties of rabbit liver tissue aminoacyl-tRNA synthetases, associated with polyribosomes, were studied under conditions of normal state and within 12 hrs after simulation of myocardium infarction. Under conditions of myocardium infarction the activity of some forms of aminoacyl-tRNA synthetase was decreased in polyribosomes and protein fractions, liberated from polyribosomes by means of washing with buffer containing 0.5 M KCl. Polyribosomes stimulated the synthetases and protected them from heat inactivation. Deterioration of the synthetases interaction with polyribosomes appears to be among the factors responsible for impairment of protein biosynthesis under conditions of myocardium infarction.

[Various characteristics of protein-synthesizing apparatus of the myocardium during total ischemia]. / Nekotorye osobennosti beloksinteziruiushchego apparata miokarda pri total'noi ishemii.

A decrease in the rate of protein synthesis as well as an increase in the synthesis time of "medium-size" polypeptide chain were detected in total rabbit myocardium ischemia, which were evaluated using rabbit myocardium cell-free protein-synthesizing systems. The decrease in the synthesis rate of total myocardial proteins was shown to depend on the state of ribosomes function. Redistribution in the pools of membrane-bound and free ribosomes as well as a decrease of polyribosomes amount in total pool of myocardial ribosomes were observed under conditions of total myocardial ischemia.

[Role of aminoacyl-tRNA-synthetases in changes in the rate of protein biosynthesis in the rabbit liver during myocardial ischemia]. / Rol' aminoatsil-tRNK-sintetaz v izmenenii skorosti biosinteza belka v pecheni krolikov pri ishemii miokarda.

Composition of high-molecular-weight aminoacyl-tRNA synthetases complexes from rabbit liver both in norm and after 12 h experimental myocardial ischemia (EMI) has been investigated. Partial redistribution of aminoacyl-tRNA synthetases activity from 1820 kD complex into 840 kD complex was observed in case of EMI which resulted in changes of protein biosynthesis rate in cell-free system.

[Distribution of aminoacyl-t-RNA-synthetase activity in rabbit liver cells during disruption of protein biosynthesis in experimental myocardia infarct]. / Raspredelenie aminoatsil-t-RNK-sintetaznoì aktivnosti v kletkakh pecheni krolikov pri narushenii biosinteza belka v usloviiakh éksperimental'nogo infarkta miokarda.

Distribution of the aminoacyl-tRNA synthetase activity has been studied in the normal rabbit liver cells and in the model of protein synthesis damage, i.e. under experimental myocardial infarction (EMI). The activity of a number of aminoacyl-tRNA synthetases in postmitochondrial and postribosomal extracts from rabbit liver homogenate has been determined to increase 12 h after EMI. Gel filtration of the postribosomal extract on Sepharose 6B shows that the activity of aminoacyl-tRNA synthetases is distributed among the fractions with Mr 1.82 x 10(6), 0.84 x 10(6) and 0.12 = 0.35 x 10(6). The first two fractions (high-molecular-weight aminoacyl-tRNA synthetase complexes) contain arginyl-, glutamyl-, isoleucyl-, leucyl-, lysyl- and valyl-tRNA synthetases, whereas the low-molecular-weight fraction contains alanyl-, arginyl-, glycyl-, phenylalanyl-, seryl-, threonyl-, tryptophanyl- and tyrosyl-tRNA synthetases. In a case of EMI all the aminoacyl-tRNA synthetases translocate from the complexes with Mr 1.82 x 10(6) into the complexes with Mr 0.84 x 10(6), what provided evidence for the possibility to regulate protein synthesis by changes in compartmentalization of aminoacyl-tRNA synthetases.

[Protein-synthesizing function of the liver of rabbits in experimental myocardial infarct]. / Beloksinteziruiushchaia funktsiia pecheni krolikov pri éksperimental'nom infarkte miokarda.

The content of serum albumin in rabbit blood was found to be lowered within the first day after reproduction of experimental myocardial infarction. The rate and the level of translation of endogenous mRNA were studied in cell-free systems from normal rabbit liver and 6-12-24 h after experimental myocardial infarction. The decrease of the total protein synthesis in the crude cell-free system from the liver of experimental animals was shown to depend on the lack of energy supply rather than on the reduced activity of the protein-synthesizing apparatus. The relative drop of protein synthesis in the cell-free system with saturating concentration of ATP, GTP and creatine phosphate is likely to be connected with a decrease in the proportion of membrane-bound polysomes.

[Amino acyl tRNA synthetase complexes in rabbit liver in experimental myocardial infarction]. / Izuchenie kompleksov aminoatsil-tRNK-sintetaz pecheni krolika pri éksperimental'nom infarkte miokarda.

The composition of high-molecular complexes of aminoacyl-tRNA-synthetases (ARSase) from the rabbit liver was studied on the first day after reproduction of the experimental myocardium infarction. The studies revealed an increase in the glutamyl-, leucyl-, lysyl- and a decrease in the glycyl- and seryl-tRNA-synthetase activities and redistribution of the last two enzymes from the composition of the complexes into a lower-molecular fraction of postribosomal supernatant fluid. Under the experimental myocardium infarction the complexes reveal a significant decrease in the content of phospholipids and variations in the electrophoretic mobility of protein fractions. An assumption is advanced that a disturbed protein biosynthesis in the liver resulted from the experimental myocardium infarction causes changes in the structural organization of the ARSase complexes.