["Starburst" conjugates of proteins with carbocene polymers, carrying low molecular weight biologically-active compounds, and their immunogenicity]. / "Zvezdoobraznye" kon''iugaty belkov s karbotsepnymi polimerami, nesushchimi nizkomolekuliarnye biologicheski aktivnye soedineniia, i ikh immunogennost'.

The synthesis of starburst polymer-protein conjugates on the basis of bovine serum albumin and horseradish peroxidase was performed with the aim to study the possibilities of regulation of the immune response against the components of the conjugates. These polymers had one-point binding between the protein and the modifying carbon-chain polymer that contained 1-vinyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (a salsolinol analogue) or bradykinin (peptide hormone) residues in its carbon chain. Changes in the chemical nature of the carbon-chain part of the polymer-protein conjugate were shown to increase or decrease the level of antibody production both against the low-molecular compounds attached to the polymeric fragments and against the protein carrier.

[The positive chronotropic effects of salsolinol on the isolated rat heart]. / Polozhitel'nye khronotropnye vliianiia sal'solinola na izolirovannom serdtse krysy.

Salsolinol (6,7-dioxy-1-methyl-1,2,3,4-tetrahydroisochinoline), a product of nonenzymatic condensation of dopamine and acetaldehyde, produced a dose-dependent positive chronotropic effect on the rat isolated perfused heart: EC = 5.6 X 10(-6) M. Inderal, a beta-adrenoreceptor antagonist (10(-5) g/ml), blocked and naloxone, an opioid receptor antagonist (3.1 X 10(-5) M), potentiated this effect. Apart from tachycardia, salsolinol induced arrhythmias which were inhibited by naloxone. Salsolinol seems to play an important role in regulating the heart performance.

[Effect of the degree of modification of trypsin amino groups with polymers on the enzymatic and conformation properties of the protein]. / Izuchenie vliianiia stepeni modifikatsii aminogrupp tripsina polimerami na fermentativnye i konformatsionnye svoistva belka.

Trypsin was modified by introducing fragments containing an azo-bond into its molecule by the reaction of free amino groups of the enzyme with an azide of 2,2'-azobisisobutryic acid. Subsequently free-radical polymerization of N-vinyl pyrrolidone was carried out with the high molecular weight initiator obtained. The degree of modification of amino groups in trypsin was n = 6 divided by 12, which distinguishes this type of modification from that earlier proposed by the authors. In that case dichlorohydrate of dimethylimidate of 2,2'-azobisisobutyric acid was used for introducing azo-bonds into the molecule of the protein, n being equal to 2-3. It is shown that under the conditions of autolytic degradation both high molecular weight initiator based on trypsin and the trypsin-PVP (poly-N-vinyl pyrrolydone) covalent conjugates exhibit higher stability than initial trypsin. The method of circular dichroism was used for comparison of conformational properties of the modified trypsin forms. An increase of the rate of thermal inactivation was found to result from conformational changes occurring on modification of the enzyme.

[Synthesis of trypsin polymer derivatives with single-point binding of the polymer-modifier and protein]. / Sintez polimernykh proizvodnykh tripsina s odnotochechnym polimera-modifikatora s belkom.

In order to produce carbon-chain covalent "star-like" conjugates of trypsin, the latter was modified by attachment of fragments containing the reaction-capable azo-bond and then N-vinyl pyrrolidone was polymerized on the resultant high molecular weight initiator. The molecular weight and proteolytic activity of the compounds were determined, and their thermal stability and resistance to autolysis were investigated. It was shown that the trypsin modified by poly-N-vinyl pyrrolidone of different molecular weights acquired greater resistance to autolytic and thermal denaturation. The spectropolarimetric examination of the conformation properties of the modified trypsin forms at varying pH demonstrated that attachment of azo-bond containing fragments to the enzyme molecule destabilized its native structure in acidic pH areas while subsequent poly-N-vinyl pyrrolidone modification increased the area of pH-stability of the conjugate as compared to the native trypsin.