[Mechanism of discrimination of tRNA(Phe) from E. coli by yeast phenylalanine-tRNA-synthetase].

Some peculiarities of aminoacylation of homologous and heterologous tRNA by yeast phenylalanyl-tRNA synthetase have been studied. It was found that the enzyme is inactivated during E. coli tRNA aminoacylation due to the formation of a pyrophosphorylated form of the enzyme.

[Pyrophosphate-dependent inactivation of tyrosyl-tRNA synthetase during aminoacylation of heterologous tRNA].

It has been shown that heterologous aminoacylation of tRNA by tyrosyl-tRNA synthetase leads to inactivation of the enzyme. Inorganic pyrophosphatase prevents the inactivation and increases the enzyme activity and aminoacylation level in a heterologous system. A putative inactivation mechanism is discussed.

[Express method of isolation of mammalian phenylalanine-tRNA-synthetase and preparation of monoclonal antibodies against this enzyme].

A rapid and efficient procedure for isolating homogeneous beef liver phenylalanyl-tRNA synthetase (EC.6.1.

[Separation and comparative characteristics of subunits of phenylalanyl-tRNA synthetase from Escherichia coli MRE-600 and Thermus thermophilus HB8].

Separation of alpha- and beta-subunits of phenylalanyl-tRNA-synthetases from E. coli MRE-600 and Thermus thermophilus HB8 using FPLC has been carried out for the first time. The separated subunits of both enzymes do not possess any detectable tRNA-amino-acylation activity.

[Phosphorylation of components of high molecular weight aminoacyl-tRNA-synthetase complex from the rabbit liver by associated casein kinase type I].

The aminoacyl-tRNA synthetase complex from rabbit liver possesses an endogenous protein kinase activity. The associated protein kinase in the complex was defined as casein kinase I. Using FPLC, a fraction of the supramolecular complex with a high level of metabolic activity was isolated; this preparation was found to be enriched in the casein kinase activity.

[Interaction of amino acyl-tRNA-synthetases from the rabbit liver with RNA and polyanions].

The interaction of aminoacyl-tRNA synthetase with RNA and polyanions was studied. The inhibition of the enzymes by polyU, polyI and heparin was demonstrated. It was found that this interaction is of limited specificity and is typical of single-stranded RNAs which possess no orderly secondary structure as well as of other polyanions possessing similar polyelectrolytic properties.

[Isolation, polypeptide composition and properties of aminoacyl-tRNA-synthetase complexes from the rabbit liver].

The procedure for isolation of the aminoacyl-tRNA-synthetase complex from rabbit liver based on the affinity chromatography on heparin- and tRNA-Sepharose has been developed. The complex has a Mr of about 1100 kD and is made up of 10 polypeptides, eight of which are aminoacyl-tRNA synthetase. The complex stability was studied under various conditions.

[Formation of lactate dehydrogenase complexes with proteins and polyelectrolytes. A possible physiological role].

The effect of polymers (proteins, polyaminoacids, polyethylenimine) on kinetic parameters of lactate dehydrogenase (LDH) from porcine skeletal muscle was studied. Activation of the enzyme which was partially due to the association of LDH dimers was observed. A hypothesis was proposed, according to which the contribution of dissociation of oligomeric enzymes in the regulation of their activity in vivo is negligible due to the equilibrium shift towards association in dissociable enzyme systems.