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A S Tikhomirova

Publications and source records attributed to A S Tikhomirova.

9 recordsLinked to original sources
PubMed1977

[Enzymatic properties of immobilized beta-galactosidase from Curvularia inaequalis].

beta-Galactosidase (EC 3.2.1.23) from fungus Curvularia inaequalis was modified by active brilliant orange KH and adsorbed on DEAE-Sephadex A-50. The lactose hydrolysis was studied in a continous flow on the column packed with the immobilized enzyme. The pH and temperatures optima for the substrate hydrolysis by the immobilized enzyme were shown to remain unchanged. A certain destabilizing effect of the matrix on the enzyme resistance to hear denaturation was observed. The activation parameters of denaturation of the native enzyme as well as those of the dye-modified and immobilized preparations were determined.

Chemical Phenomena↗
PubMedDate not supplied

[Method for immobilization of enzymic preparations catalyzing the splitting of low-molecular substrates].

A new method is suggested for immobilizing enzymes, catalyzing the splitting of low-molecular substrates. It consists in applying the layer of the enzymic preparation with a filler and a stabilizer onto the inert carrier by the rolling-up method in the dredging box and the subsequent coating of particles with a semipermeable film. The efficiency of the mentioned method is examined in two enzymic preparations: beta-galactosidase and beta-fructofuranosidase. Its advantages are discussed, the main of which are the simplicity of technology possibilities of using the enzymes technical preparations, maximal preservation of native properties.

Drug Stability↗
PubMedDate not supplied

[Preparation and properties of beta-galactosidase linked covalently with KM-cellulose].

Fungal beta-galactosidase was immobilized by covalent binding with KM-cellulose. The resultant preparation contained 3 mg protein per 1 g carrier; its specific activity was 65% of the initial one. As a result of immobilization pH optimum remained unchanged whereas the temperature optimum decreased from 65 degrees to 50 degrees. The seemings Km of the immobilized enzyme varied insignificantly as compared with Km of the soluble enzyme.

Binding Sites↗
PubMedDate not supplied

[Factors influencing the biosynthesis of beta-galactosidase in Alternaria tenuis].

The effect of pH, carbon sources, and some organic substances on the biosynthesis of beta-galactosidase was studied in Alternaria tenuis on a defined medium that had been optimized by the method of mathematical planning of experiments. Optimal conditions for the production of the enzyme and its liberation into the cultural broth were maintained by adding 2 per cent soya flour to the medium and 0.1 M phosphate-citrate buffer pH 3.0. The production of the enzyme was increased by 3 to 4 times. The biosynthesis of beta-galactosidase by Alternaria tenuis is of an induced nature.

Alternaria↗
PubMedDate not supplied

[Production and properties of a beta-galactosidase preparation from Alternaria tenuis].

Different methods of the preparation of fungal beta-galactosidase from the 72-hour culture of Alternaria tenuis were tested: lyophilization of the culture liquid, precipitation with ethanol, acetone, ammonium sulphate. Optimal results were obtained with precipitation by 1.5 acetone volume. Studies of the properties of fungal beta-galactosidase demonstrated that the preparation retained its activity during 22 month storage at 5 degrees C. The fungal preparation had pH optimum at a more acidic zone (4.2 versus 6.9), was active in a wider pH range 2.8-5.7 and 6.2-7.5), had a much higher temperature optimum (65 degrees and 30 degrees) and better thermostability as compared with the yeast preparation. Data on other properties of the preparation are presented.

Alternaria↗
PubMedDate not supplied

[Optimization of the conditions for beta-galactosidase biosynthesis in eukaryotes].

Liquid whey can be subsituted by dry whey in the growth medium for Saccharomyces fragilis producing endocellular beta-galactosidase. The total biosynthesis of beta-galactosidase by the yeast on the medium containing dry whey can be increased by 40-50 percent as a result of additional stepwise introduction of lactose into the medium or optimization of the medium by mathematical planning of the experiment. Constructive metabolism of the yeast is not correlated with the rate of biosynthesis of beta-galactosidase. Damages in constructive metabolism of facultative anaerobes - yeast cultures - caused by the limitation of aeration result in an increase of the rate of beta-galactosidase biosynthesis. Such a correlation between the rate of the enzyme biosynthesis and the degree of aeration of the culture is not found in strict aerobes - fungi Alternaria tenuis and Curvularia inaequalis.

Aerobiosis↗
PubMedDate not supplied

[Ion exchange purification of some enzymes on KMT carboxyl cation exchanges].

Highly purfied preparations of the enzymes--yeast beta-fructofuranosidase, fungal beta-galactosidase and bacterial proteases have been isolated from crude preparations or culture liquids by adsorption on KMT microporous carboxyl cation exchanger. During desorption the enzyme activity has fully recovered and the specific activity increased 4.5-fold for beta-galactosidase and 54-fold for proteases.

Bacillus subtilis↗