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Iu Ia Markushin

Publications and source records attributed to Iu Ia Markushin.

6 recordsLinked to original sources
PubMed1996

[Increase in the effectiveness of site-specific cleavage of target DNA by tetranucleotide bleomycin derivatives using oligonucleotide-effectors].

The efficiency of site-specific interaction of target DNA with bleomycin derivatives of short nucleotides can be significantly increased using flanking effector oligonucleotides. The cleavage of a 20-mer single-stranded target DNA by a tetranucleotide containing a bleomycin A5 residue at the 5'-end was studied in the presence of effector oligonucleotides bearing phenazine residues at the 5'- and 3'-ends. In the presence of two effectors, the extent of the target DNA modification at 37 degrees C increased from 20 to 70%. Site-specific cleavage occurs, by up to 90%, at a single site of the target DNA. The melting temperature of the complementary complex formed by the bleomycin A5-modified tetranucleotide and target DNA in the presence of two effectors was 45 degrees C, whereas in the absence of the effectors, below 7 degrees C.

Antibiotics, Antineoplastic↗
PubMedDate not supplied

[Effect of linker length on the photomodification process of tyrosine residues in N-(tyrosyl)-N'-(5-azido-2-nitrobenzoyl)diaminoalkanes].

N-(Tyrosyl)-N'-(5-azido-2-nitrobenzoyl)-1,4-diaminobutane, containing a Tyr residue connected with the photoreactive aryl azide group through the diaminobutylene linker, was synthesized as a model for studying the photomodification of Tyr residues in proteins. This compound and the compound with a shorter, 1,2-diaminoethylene linker, obtained previously, were subjected to computer modeling to find their minimal-energy conformations. The aromatic rings of Tyr and 5-azido-2-nitrobenzoic acid residues in the latter compound were localized in parallel planes at a distance of approximately 0.3 nm between them and were shown to be implicated in stacking interactions. On the contrary, the planes of aromatic rings of the former compound with a longer, diaminobutylene linker were found to be situated perpendicularly to each other, with the distance between the centers of the rings being approximately 0.6 nm. The computer analysis was confirmed by experimental results: when studying the photomodification of the compound with the diaminobutylene linker, neither stable products of the Tyr photomodification nor unstable products capable of transformation into stable products in the dark were found. On the contrary, such products were previously identified in the case of the compound with diaminoethylene linker. The formation of amino, nitro, azoxy, and azo derivatives was common for the photomodification of both compounds.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

[Changes in the membrane permeability of erythrocytes in the presence of heparin].

It has been found by the conductometric impulse method that membrane conductivity of human erythrocytes rises about 70 times at heparin concentration in blood samples above 0.2 mg/ml. The presence of edetic acid (EDTA) in blood samples inhibits the rise of membrane conductivity on addition of heparin.

Cell Membrane Permeability↗