[Preparation of monospecific antibodies against isoform 2 of translation elongation factor 1A (eEF1A2)].

Amino acid sequences of eukaryotic translation elongation factor isoform 1 (eEF1A1) and 2 (eEF1A2) were compared and two peptide fragments of eEF1A2 were chosen as linear antigenic determinants for generation of monospecific antipeptide antibodies. Selected peptides were synthesized, conjugated to bovine serum albumin (BSA) and used for mice immunizations. Antibodies, produced against the eEF1A2 fragment 330-343 conjugated to BSA, specifically recognized this isoform in the native and partially denatured states but did not interact with the eEF1A1 isoform. It was shown that these monospecific anti-eEF1A2 antibodies could be employed for eEF1A2 detection both by enzyme-linked immunosorbent assay and by immunoblotting.

Renaturation of rabbit liver aminoacyl-tRNA synthetases by 80S ribosomes.

Protein biosynthesis machinery is thought to be mostly compartmentalised within the mammalian cell, involving direct interactions between different components of the translation apparatus. The present research concerns the functional meaning of the interaction between the rabbit liver aminoacyl-tRNA synthetases and 80S ribosomes. We have shown that rabbit liver 80S ribosomes are able to enhance the activity of leucyl-tRNA synthetase, which is a component of high-molecular weight aminoacyl-tRNA synthetase complex, and phenylalanyl-tRNA synthetase not associated within this complex. The ribosomes increase the initial rate of both the total reaction of tRNA aminoacylation and the first step of this reaction, the formation of leucyladenylate. Moreover, a positive cooperativity of the tRNA interaction with two binding sites of leucyl-tRNA synthetase is also increased in the presence of highly purified 80S ribosomes. The effect of 80S ribosomes on partly denatured leucyl-tRNA synthetase and phenylalanyl-tRNA synthetase and the protection by 80S ribosomes of both enzymes against inactivation indicate a refolding and stabilising capacity of the ribosomes. It is concluded that the interaction of aminoacyl-tRNA synthetases and 80S ribosomes is important for the maintenance of an active conformation of the enzymes.

[Structure-functional properties of eukaryotic aminoacyl-tRNA synthetase]. / Strukturno-funktsional'nye osobennosti ékarioticheskikh aminoatsil- t-RNK sintetaz.

Data on structural and functional peculiarities of eukaryotic aminoacyl-tRNA synthetases (structure, supermolecular organization, and localization in eukaryotic cell) are reviewed. The functional significance of aminoacyl-tRNA synthetase association with high molecular weight complexes and other cellular components is discussed.

[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.

[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.

[Aminoacyl-tRNA-synthetases and their high molecular weight complexes in experimental myocardial ischemia]. / Aminoatsil-tRNK-sintetazy i ikh vysokomolekuliarnye kompleksy pri éksperimental'noi ishemii miokarda.

A number of aminoacyl-tRNA synthetases from rabbit liver during experimental myocardial infarction and from pig myocardium upon 15-min of autolysis were found to increase their activity in aminoacylation. Direct correlations between the activities of high molecular weight complexes and of the total extracts were not observed. It was shown that the specific activity of endogenous inorganic pyrophosphatase increased markedly during the ischemia of myocardium both in total myocardium extracts and in high molecular weight complexes.

[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.

[tRNA- and aminoacyl-tRNA in the rabbit liver in ontogenesis (author's transl)]. / tRNS- und Aminoazyl-tRNS-Synthese in der Leber von Kaninchen in der Ontogenese.

The acceptor capacity of tRNAs and tRNA-synthetases activities of liver extracts was compared for rabbits of different age groups. The level of maximum tRNA aminoacylation in vitro of newborn rabbit (3-5 days) liver for glycine, glutamic acid, leucine, tryptophan, and phenylalanine and tRNA of old rabbits (5 years) liver for glutamic acid, leucine, phenylalanine, and glycine was 1,5-3 times lesser in comparison to that of 1 and 2 years rabbits. The pool of endogenous aminoacyl-tRNAs in 3-5 days rabbits liver was also considerably lower for above mentioned amino acids. The results of short-term heating of tRNA preparations in the presence of Mg2- given the possibility to assume that the decreases tRNA preparations in the presence of Mg2+ give the possibility to assume that the decreases tRNA acceptor activity of the newborn animals depends upon the presence of tRNA inactive conformers. Another reason is the greater loss of the CCA-end in mentioned tRNA. None of these factors in the reason of low acceptor activity of old rabbit liver tRNA which seems to be caused by more considerable disturbances in he molecular structure. Aminoacyl-tRNA-synthetases activities of liver extracts of the same age groups increases during development of animals and decrease subsequently in the liver of old (5 years) rabbits. However, dynamics and quantitative characteristics of these changes are not similar for enzymes of different amino acid specificities.