PubMed Health⌕ Search

Biomedical subjects

V V Tsibanov

Publications and source records attributed to V V Tsibanov.

13 recordsLinked to original sources
PubMed1992

[Consumption of amino acids by Escherichia coli--a producer of recombinant proteins].

The dynamics of amino acid consumption from the medium by Escherichia coli 1864, a strain producing recombinant protein was studied. It was shown that the strain actively used glutamate and aspartate from the medium, which was determined by the leading role of the amino acids in nitrogen metabolism. The strain also consumed threonine, glycine and alanine capable of effectively providing the culture with metabolic energy.

Albumins↗
PubMed1990

[Intracellular aminopeptidase from Xanthomonas rubrilineans, hydrolyzing alpha-amino acid esters and cefalexin].

The aminopeptidase was isolated from cell-free extracts of Xanthomonas rubrilineans by protein precipitation by isopropyl ester with subsequent purification by affinity chromatography on CABS-Sepharose, bacitracin-Sepharose, gel filtration through Sephadex G-200 and ultrafiltration, the total yield being 32% with 2200-fold purification. The enzyme was homogeneous during SDS-PAAG electrophoresis. Apart from the broad spectrum of the peptidase activity, aminopeptidase possesses a hydrolase activity towards beta-lactam antibiotics and an esterase activity towards L- and D-amino acids. Besides, this enzyme catalyzes the acetyl transfer reaction during cephalexin synthesis from the D-phenylglycine ester and 7-aminodesacetoxycephalosporanic acid. The maximal enzyme activity during L-Ala-pNA and cephalexin hydrolysis is manifested at pH 6.5. The enzyme is stable at pH 4.0-8.0 and is inhibited by o-phenanthroline, p-chloromercuribenzoate, hydrogen acetate and N-bromosuccinimide. The molecular mass of the enzyme is 270-280 kDa. The enzyme is a tetramer; the molecular mass of each of its four subunits is 70 +/- 2 kDa. The isoelectric point for the enzyme is 6.8. The amino acid composition of the enzyme appears as follows: Asp63, Thr33, Ser32, Glu72, Gly55, 1/2Cys3-4, Val45, Ile24, Leu53, Tyr23, Phe24, Lys23, His16, Arg36, Pro60, Met25, Ala55.

Amino Acid Sequence↗
PubMed1989

[Effect of antibiotics on excretion of various microbial metabolites with feces].

Concentrations of volatile fatty acids, free amino acids, ammonia, protein, carbohydrates, carboxylic acids and some cations were determined in feces of intact animals (rats) chromatographically and spectroscopically. Oral administration of 8 chemotherapeutic drugs in the therapeutic doses to the animals resulted in changing excretion of the majority of the above compounds associated with vital activity of the large intestine microflora which depended on the drug type. Investigation of metabolic activity of normal microflora of the gastrointestinal tract is shown promising for estimation of intestinal microbial biocenosis.

Amino Acids↗
PubMed1989

[Study of amino acid utilization by isogenic strains of Escherichia coli in relation to the culture growth and biosynthesis of penicillin amidase].

Dynamics of free amino acid utilization by isogenic strains of Escherichia coli differing in intensity of their growth and levels of penicillin acylase biosynthesis in media containing corn steep liquor or peptone was studied. It was shown that in both the media some amino acids such as serine, threonine, glutaminic and asparaginic acids were actively utilized by the strains mainly during the culture intensive growth while others such as glycine, alanine and tyrosine were actively utilized during the enzyme biosynthesis. Intensively utilized arginine and proline were probably used for the growth and biosynthesis. The other amino acids were not utilized completely from the media. The lowest levels of their utilization were observed when the strains were cultivated in the medium with peptone.

Amidohydrolases↗
PubMed1988

[Conditions for immobilizing Streptomyces erythreus in a calcium alginate gel and the apparatus setup for the process].

A laboratory unit for production of calcium alginate gel granules with immobilized microorganisms is described. It provides sterile production of particles from tens micrometers to 2 mm in diameter. Expediency of using biocatalysts in the form of fine granules is exemplified with a number of immobilized microorganisms. Conditions for immobilizing the erythromycin producing organism by its incorporation into the calcium alginate gel were studied. Viability of the actinomycete in the gel was shown by consumption of the nutrients and biosynthesis of the antibiotic.

Alginates↗
PubMed1985

[Isolation of protein hydrolysates by using immobilized bacterial peptide hydrolases].

Preparation of medical protein hydrolysates with the use of complete hydrolysis of proteins by bacterial enzyme complexes, such as protosubtilin G10x and bacterial peptidase immobilized on aminosilylated alumina was shown to be possible. The activity, thermostability and substrate specificity of the heterogeneous biocatalysts were studied. The integral kinetics of the hydrolysis of sodium caseinate and peptides included in partial acid and enzymatic casein hydrolyzates and blood was investigated. The engineering approaches to mathematical simulation of the bioproteolysis kinetics and the results of their use in processing of the experimental data are discussed.

Aluminum Oxide↗
PubMed1985

[Sorption of amino acids from aqueous solutions on activated charcoal].

Various methods for quantitative description of amino acid sorption from solutions for parenteral nutrition on activated charcoal were studied under dynamic and static conditions. With the use of the well-known Freindlich and Langmuir absorption isotherms it was shown to be possible to describe in a simplified way the complex multicomponent process of sorption of the amino acids and to estimate their loss at the filtration stage.

Absorption↗
PubMedDate not supplied

[Effect of carbohydrates in the culture medium on amino acid composition of a cephalosporin C producer].

The intracellular and extracellular amino acid composition of an auxotrophic methionine-deficient strain of Acremonium chrysogenum was studied in respect of the content of various carbohydrates in the fermentation medium. In the presence of glucose, an intensive involvement of exogenous DL-methionine into the cell metabolism was observed at earlier stages than in the presence of dextran or succrose. The total content of intracellular amino acids was lower in the cells grown on the medium with glucose. The production of cephalosporin C depended on the intracellular content of methionine, glutamic acid and lysine.

Acremonium↗
PubMedDate not supplied

[Effect of parenterally administered baker's yeast autolysates on normalization of the plasma aminogram in acute hepatitis in the rabbit].

A study was made of the effect of autolysine--a mixture of amino acids and lowest peptides, obtained by autolysis of baker yeast biomass, on the normalization of blood plasma and brain tissue aminogram in rabbits with acute hepatitis caused by D-galactosamine. 3,6% isoleucine, leucine and valine as well as 0,9% sodium chloride served as control. Parenteral administration of autolysine in an amount of 4 g conventional protein per kg bw a day entailed a substantial normalization of the amino acid spectrum of blood plasma and brain.

Acute Disease↗
PubMedDate not supplied

[Casein hydrolysis by immobilized protosubtilin].

A study was made of the kinetics of sodium caseinate hydrolysis by protosubtilin G10X (Bac. subtilis producer) immobilized on silica gel with the aid of glutar dialdehyde. Optimal conditions for making the process were selected (pH 8.5, temperature 60 degree C, substrate concentration 0.3%). The apparent kinetic parameters of the reaction were calculated. An empiric equation that can be used for practical calculation was derived from the Michaelis-Menten equation with the use of the values obtained (Km = 2.48 +/- 0.10 micrometer/ml, Vmax = 25.6 +/- 1.9 micrometer/min/mg conventional protein).

Bacillus subtilis↗
PubMedDate not supplied

[Immobilized lipase from Rhizopus oryzae 14-14].

Properties of lipase immobilized from Rhizopus oryzae 14-14 immobilized on inorganic supports-aluminium oxide and silica gel-were investigated. Aluminium oxide immobilized lipase retained 23% of its initial activity when tributyrin was used as substrate. pH optimum of action of immobilized lipase was at 8.75, i.e. it was shifted toward the more alkaline area as compared to pH optimum of the non-immobilized enzyme which was in the area of 7.0-7.8. The temperature optimum of action of the immobilized enzyme was 50 degrees, i.e. it was at higher temperatures than that of the initial enzyme.

Enzymes, Immobilized↗
PubMedDate not supplied

[Quantitative determination of the peptides in protein hydrolysates for medical use].

The paper describes an assay of medium size peptides in the amino peptide--a protein hydrolysate for parenteral nutrition, manufactured by home industry. The assay is based on an amino acid analysis of the preparation as well as on the use of the magnitudes of amine and total nitrogen determined by the conventional techniques accepted in protein chemistry.

Amino Acids↗