[Interaction of amino acyl-tRNA-synthetases from the rabbit liver with RNA and polyanions]. / Vzaimodeistvie aminoatil-tRNK-sintetaz iz pecheni krolika s RNK i polianionami.

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. Data from kinetic analysis and lysyl-tRNA synthetase modification by pyridoxal phosphate are suggestive of participation of the tRNA binding site in the enzyme interaction with polyanions.

[Isolation, polypeptide composition and properties of aminoacyl-tRNA-synthetase complexes from the rabbit liver]. / Vydelenie, polipeptidnyi sostav i svoistva kompleksa aminoatsil-tRNA-sintetaz iz pecheni krolika.

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. The data obtained are discussed in terms of the involvement of hydrophobic domains of aminoacyl-tRNA synthetases in the stabilization of the complex.

[Possible role of the macromolecular environment in enzyme functioning in the cell. Interaction of E. coli beta-galactosidase with endogenous polycationic proteins and kinetic parameters of the enzyme in situ]. / Vozmozhnaia rol' makromolekuliarnogo okruzheniia fermentov v ikh funktsionirovanii v kletke. Vzaimodeistvie beta-galaktozidazy E. coli s éndogennymi polikationnymi belkami i issledovanie kineticheskikh parametrov fermenta in situ.

The effect of endogenous protein polycations on the kinetic properties of beta-galactosidase was studied. The dependence of kinetic properties of the enzyme (Km and V) in situ at the growth stage of microbial cultures was demonstrated. The observed phenomenon may be explained by the enzyme interaction with endogenous polycations. This interaction is of limited specificity, since it involves different types of biomolecules which display similar polyelectrolyte properties.

[Isolation and properties of prostaglandin H synthetase immobilized in insoluble polyelectrolyte complexes]. / Poluchenie i svoistva prostaglandin-H-sintetazy, immobilizovannoi v nerastvorimykh poliélektrolitnykh kompleksakh.

Immobilization of prostaglandin-H-synthetase (EC 1.14.99.1) of the microsomal fraction of ram vesicular gland in the microparticles of insoluble polyelectrolyte complexes by non-covalent incorporation was studied. It was shown that immobilization occurs with a high efficiency and high activity yield (40-70%). Non-specific reversible inhibition of the enzyme by the polycationic component of the complex was demonstrated. The dependencies of activity of the native and immobilized enzymes on pH, temperature and substrate (adrenaline and arachidonic acid) were studied. The immobilized enzyme had an increased thermal stability as compared to the native one; the thermoinactivation rate constant was decreased 3-7 times. The biexponential type of the curve of the rependence of activity vs. time for the native enzyme and the transformation of the curve into a simple exponential form for the immobilized enzyme were observed.

[Formation of lactate dehydrogenase complexes with proteins and polyelectrolytes. A possible physiological role]. / Obrazovanie kompleksov laktatdegidrogenazy s belkami i poliélektrolitami. Vozmozhnaia fiziologicheskaia rol'.

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.