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Biomedical subjects

N F Kazanskaia

Publications and source records attributed to N F Kazanskaia.

At least 19 recordsLinked to original sources
PubMed2003

[The role of the components of the renin-angiotensin system in the ocular tissues in norm and pathology].

Different components of the renin-angiotensin system (RAS), whose content and activity are predetermined by local factors, are generated in the ocular tissue structures. The local eye RAS plays an important role in pathogenesis of different eye diseases and in the local manifestations of general pathological processes. Therefore, a study of the eye RAS components in norm and in disease contributes to understanding the pathogenesis of eye diseases and opens up new possibilities for an adequate treatment. The RAS components in the lacrimal fluid can be an important characteristics of such diseases like keratitis, diabetic retinopathy etc.

Bradykinin↗
PubMed1998

[Phase transition in the matrix as a regulator of enzymatic activity of proteinases].

The kinetic behavior of proteolytic enzymes immobilized in thermosensitive hydrogels was studied at the phase transition (collapse) of the carriers. The dependence of the activity of immobilized enzymes on the state of the matrix allows the use of the hydrogel phase transition to regulate the activity of immobilized enzymes. Several cases of such regulation were demonstrated.

Acrylic Resins↗
PubMed1995

[Structure and biological properties of a conjugate of Bowman-Birk type soy proteinase inhibitor with a block copolymer of ethylene oxide and propylene oxide].

The structure of the conjugate of Bowman-Birk soybean proteinase inhibitor (BBI) with the block copolymer of ethylene oxide and propylene oxide (proxanol) containing five moles of proxanol per mole of protein, has been studied. Data from reverse phase hydrophobic HPLC suggest that the conjugate is less hydrophobic compared to native BBI. A shift of the second derivative UV absorption spectrum for the conjugate towards the shortwave region indicates a greater accessibility of the Tyr-59 residue localized in the interdomain region of the BBI molecule for the solvent. It has been assumed that the conjugate-induced increase in Ki for chymotrypsin may be due to both disturbances in the intact structure of the interdomain region of BBI and screening of the anti-chymotrypsin reactive center as a result of hydrophobic interactions of propylene oxide blocks of proxanol with exposed hydrophobic groups around the reactive center. Supporting evidence in favour of BBI molecule hydrophilization as a result of modification by proxanol can be derived from decreased conjugate penetration into intestinal epithelial cells as well as from the slow elimination of the conjugate from mouse blood stream.

Animals↗
PubMed1994

[Determination of solvent accessibility of residues of aromatic amino acids in proteins using the second derivative of the UV-absorption spectrum].

A new method for determining the solvent accessibility of tyrosine and tryptophan residues in proteins from the wavelengths of absorption peak maxima in secondary derivatives of UV absorption spectra has been developed. Analytical expressions for calculating the number of groups in latent and exposed states of amino acid residues in protein globules were obtained on the basis of the previously elaborated mathematical model of spectral changes observed during the transition between those respective states. The new procedure was used to analyze sixteen proteins and showed a good correlation between the experimental results and literary data.

Models, Theoretical↗
PubMed1994

[Inhibition of elastin hydrolysis, catalyzed by human leukocyte elastase and cathepsin G, by the Bowman-Birk type soy inhibitor].

Cathepsin G stimulates the hydrolysis of elastin from bovine neck ligament catalyzed by human leukocyte elastase. Stimulation factor depends on the ratio of the enzyme concentrations and ionic strength and equals 1.0-2.0. The classical Bowman-Birk inhibitor from soya retards strongly the hydrolysis of elastin catalyzed by leukocyte elastase, cathepsin G and the mixture of both. The inhibitory effect is practically unaffected by the adsorption of the enzymes on elastin, prolongation of the enzymatic reaction and ionic strength.

Amino Acid Sequence↗
PubMed1994

[Inhibitors as factors regulating proteolysis].

Functions of proteinase inhibitors, connected with their ability to normalise proteolysis, are reviewed briefly. Arguments are suggested on favour of using the inhibitors as drugs for treatment of some diseases.

Animals↗
PubMed1994

[A quantitative method for evaluating the structure and conformational stability of proteins by second derivative UV-spectroscopy].

A quantitative method is suggested for estimating the structure and conformational stability of proteins based on the individual absorbance of Tyr residues in the second derivative UV spectra. Subtilisins Carlsberg, BPN' and 72 were chosen as the model proteins. The values of the increase of the Tyr absorption at 282.3 nm upon the total denaturation of the proteins made it possible to calculate the number of the exposed and "buried" tyrosine residues in the native proteins. A mathematical model of spectrum changes during the transition of Tyr residues from the "buried" to exposed form is suggested. The method is useful for the determination of the denaturation constants of proteins bearing "buried" tyrosine residues.

Models, Theoretical↗
PubMed1994

[Anomalous temperature dependence of the activity of immobilized alpha-chymotrypsin preparations].

Catalytic activity of alpha-chymotrypsin preparations covalently included in the matrix of the poly-N-isopropylacrylamide gel does not follow Arrhenius equation above the low critical temperature of the polymer dissolution. Starting from this temperature, at which the changes of polymer structure takes place (hydrophobization), the temperature increase results in a rate lowering for the chemical reaction catalyzed by the enzyme. This phenomenon is reversible. A correlation between temperature dependence of the immobilized alpha-chymotrypsin activity and the dehydration degree of the carrier is observed. The decrease of the water content in the matrix causes a change of the substrate specificity of the immobilized alpha-chymotrypsin.

Acrylamides↗
PubMed1993

[Inhibition of cathepsin G and elastase from human granulocytes by multiple forms of the Bowman-Birk type of soy inhibitor].

A classical soybean inhibitor (Bowman-Birk inhibitor, BBI 2-IV) and two high molecular weight glycine-enriched inhibitors of the same type (3-II and 4-II) have been isolated, purified to homogeneity and characterized. All of the BBI isoforms have been found to effectively inhibit cathepsin G and human granulocyte elastase. The constants for leucocyte cathepsin G inhibition by classical BBI 2-IV (Ki = 1.2 x 10(-9) M) and high molecular mass BBI 3-II (Ki = 8.0 x 10(-8) M) as well as for leucocyte elastase inhibition by high molecular mass BBI 3-II (Ki = 1.1 x 10(-7) M) have been determined.

Amino Acids↗
PubMed1993

[Conjugation of classic Bowman-Birk soy inhibitor with a copolymer of ethylene oxide and propylene oxide].

A classical soybean inhibitor of the Bowman-Birk type (BBI) with a copolymer of ethylene oxide and propylene oxide (PE) has been synthesized. The BBI-PE conjugate contain five covalently bound polymeric chains per one protein molecule and retains its capacity to inhibit trypsin (Ki = 10(-10) M), alpha-chymotrypsin (Ki = 7 x 10(-8) M) and human granulocyte elastase (Ki = 3 x 10(-8) M). The preservation of the antiproteinase activity in the antichymotrypsin center creates a prerequisite for the manifestation of the anticarcinogenic effect of the inhibitor.

Chymotrypsin↗
PubMed1993

[Bowman-Birk soy inhibitor as an affinity ligand for isolating leukocyte elastase. Inhibition of elastin hydrolysis, catalyzed by leukocyte elastase].

A one-step procedure for human leukocyte elastase purification using an affinity adsorbent based on protein soybean Bowman-Birk proteinase inhibitor has been developed. The leukocyte elastase was purified 70-fold with a 70-100% yield. The enzyme preparations did not contain cathepsin G and displayed a high specific activity. The soybean Bowman-Birk type inhibitor effectively inhibited the elastin hydrolysis by leukocyte elastase both when the enzyme and the inhibitor were simultaneously added to the substrate and after preliminary elastase adsorption on elastin. The inhibitory effect was preserved at high degrees of elastin hydrolysis.

Affinity Labels↗
PubMed1990

[Function of angiotensin-converting enzyme on matrices].

The binding of the angiotensin-converting enzyme from bovine lung on BrCN-activated Sepharose, CH- and AH-Sepharoses as well as on AH-Sepharose via the carbohydrate fragment of the glycoprotein molecule modulates the possible microenvironment of the enzyme in vivo. It has been shown that the close interaction of the enzyme with the carbohydrate matrix may increase the absolute values of catalytic constants for the hydrolysis of certain substrates. The binding of the angiotensin-converting enzyme to the matrices markedly changes the enzyme activation by chloride ions by causing a shift in the activity optima towards lower activator concentrations.

Amino Acid Sequence↗
PubMed1990

[Physico-chemical characteristics of angiotensin-converting enzyme from the bovine lung].

The angiotensin-converting enzyme from bovine lung was isolated by chromatography with a 25-30% yield and purified 2200-2600-fold. The active molecule concentration in the enzyme preparations was 70-100% as could be judged from titration by inhibitor SQ 20,881. The molecular mass of the enzyme according to electrophoretic data is about 132 kDa; the maximal radius of the enzyme molecule as determined by electron microscopy is 68 +/- 9 A. Five enzyme isoforms with pI of 4.85, 4.7, 4.54, 4.38 and 4.3, respectively, were identified. The kinetic parameters of hydrolysis of three synthetic peptide substrates and the constants of activation of the substrate (Z-Phe-His-Leu) hydrolysis by chloride anions were determined.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1989

[A method for determining plasmin by the rate of fibrin gel lysis].

A simple and sensitive method has been developed to assess the fibrinolytic activity of plasmin from the change in the column height of fibrin gel. Two conditions were used: 1) 37 degrees C and 16 h incubation at plasmin concentrations of 0.5-50 micrograms/ml and 2) 25 degrees C and 1-2.5 h incubation at plasmin concentrations of 50-1000 micrograms/ml. The method permits to observe the kinetics of fibrinolysis at plasmin concentrations higher that 10 micrograms/ml. The results have shown that the method is applicable for quantitation of plasminogen in human plasma. The method is precise and well reproducible.

Chromatography, Affinity↗
PubMed1989

[Kinetics of dissolution of solid protein substrates by proteinases. Selection of the reaction mechanism].

Experimental data on the rate of enzymatic degradation of a solid protein phase in relation to reagent concentrations in the gelatin gel--proteolytic enzyme solution system was obtained. It was shown that different transformations of the Michaelis-Menten equation do not provide any satisfactory description of the reaction kinetics. A method for the discrimination of putative reaction mechanisms based on the analysis of effective values of constants in the general equation for the rates of dissolution of proteins with different molecular weights was proposed. The experimental results are in favour of a two-step consecutive mechanism taking account of surface concentrations of the adsorbed enzyme and hydrolyzable bonds.

Kinetics↗