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I S Kulaev

Publications and source records attributed to I S Kulaev.

At least 73 records · Page 4Linked to original sources
PubMed1987

Subcellular localization of enzymes in Streptomyces aureofaciens and its alteration by benzyl thiocyanate. II. Anhydrotetracycline oxygenase and glucose-6-phosphate dehydrogenase.

The localization of anhydrotetracycline oxygenase and glucose-6-phosphate dehydrogenase (EC 1.1.1.49) was studied by determining the enzyme activities in subcellular fractions obtained by differential centrifugation of the mycelia of Streptomyces aureofaciens after lysozyme treatment. Glucose-6-phosphate dehydrogenase was a typical cytoplasmic enzyme both in the low- and high-production strain. Anhydrotetracycline oxygenase was found in the membrane fraction of the low-production strain. In the high-production strain, it was detected in several fractions, the highest activity being found in cytoplasm. The presence of 10 microM benzyl thiocyanate in the culture medium significantly changed the distribution of the latter enzyme in both strains. The redistribution of the enzymes is discussed with respect to tetracycline over-production.

Cell Fractionation↗
PubMed1986

[Various physico-chemical properties of lytic proteinase L2 of the enzyme preparation lysoamidase isolated from bacteria of Pseudomonadaceae family].

Some physico-chemical properties of lytic proteinase L2 isolated from the enzymatic microbial preparation of lysoamidase were studied. The molecular mass of the enzyme is 15 000 Da, pI is 5.3. The enzyme hydrolyzes casein as well as the cells and cell walls of Staphylococcus aureus 209-P. The pH optimum of casein hydrolysis lies at 9.5; that for cell wall hydrolysis at 8.0. The temperature optimum for casein hydrolysis and cell lysis lies at 55 degrees C and 65 degrees C, respectively. The enzyme proteolytic activity is inhibited by serine proteinase inhibitors in a greater degree than the lytic activity. 50% of the proteolytic and lytic activities is lost upon enzyme heating for 15 min at 65 degrees C.

Bacteriolysis↗
PubMed1982

[Properties of polyphosphate phosphohydrolase of the "leaky" mutant Neurospora crassa with respect to the specific enzyme].

Some properties of polyphosphate phosphohydrolase from N. crassa strain ad-6.28610a and from its mutant with a decreased polyphosphate phosphohydrolase activity were compared. It was shown that the pH optimum for both enzyme species lies within the range of 7.1-7.3; the temperature optimum is 45 degrees. The mutant polyphosphate phosphohydrolase has a V value, which is 2 times less than that of the parent strain, and possesses a higher thermal inactivation stability. The enzymes of both cultures have practically identical values of Km(app), which depend on the length of the substrate chain. Upon transition from polyphosphate n = 9 to polyphosphate n = 180 the enzyme affinity is increased. Electrophoretic separation of cell-free extract proteins in polyacrylamide gel revealed the existence of two enzyme isoforms in both strains. The electrophoretic mobility of these isoforms are identical in both cultures. Biosynthesis of polyphosphate phosphohydrolase and tripolyphosphatase of N. crassa, unlike that of bacteria, is not controlled by a system common for alkaline phosphatase.

Acid Anhydride Hydrolases↗
PubMed1982

[Interaction of alkaline phosphatase and acid phospholipids in E. coli cells and artificial membranes].

The synthesis of alkaline phosphatase, an enzyme secreted by E. coli, is decreased in the cells pretreated with the lipotropic antibiotic polymixin prior to derepression. The decrease of the enzyme synthesis in the cell is correlated with the changes in the intracellular and intramembrane ratios of acid phospholipids, presumably at the level of the cytoplasmic membrane. The interaction between alkaline phosphatase and artificial lipid membranes has been shown to be a function of pH and ionic strength and is increased in the liposomes rich in acid phospholipids and decreased in the polymixin-treated liposomes.

Alkaline Phosphatase↗
PubMed1982

[Inhibiting effect of concanavalin A on certain biosynthetic processes in spheroplasts of the yeast Saccharomyces cerevisiae].

The effect of concanavalin A on biosynthesis of nucleic acids, proteins, structural polysaccharides and glycoproteins of the yeast cell membrane and of enzymes having different localization in the cell as well as on other processes occurring in spheroplasts of the yeasts Saccharomyces cerevisiae IBPhM-350 and CCY 21-4-13 were studied. In both yeast strains lectin strongly inhibited total protein synthesis and produced a weaker inhibiting effect on DNA and RNA synthesis. This was accompanied by a decrease of the activity of the majority of already known enzymes (acid phosphatase, invertase, alpha-glucosidase, polyphosphatase, pyrophosphatase, ATPase) and glucose consumption. In addition concanavalin A inhibited the synthesis of structural components of the yeast cell membrane, i.e. mannane and glucane. The data obtained suggest that lectin (50 microgram/ml or higher) has a toxic effect on yeast spheroplasts (or protoplasts).

Cell Membrane↗
PubMed1981

Accumulation of pyrophosphate and other energy-rich phosphorous compounds under various conditions of yeast growth.

In the cells of hybrid yeast strain Saccharomyces N.C.Y.C. 644 SU3 (Karlsberg collection), a large amount of pyrophosphate (30-300 micro mol per g of dry weight) accumulates whatever the aeration conditions and the contest of glucose in the medium. The content of pyrophosphate is 10-100 times higher than that of ATP. At the early and mid-exponential growth phases two maxima of pyrophosphate accumulation are observable. The periods of maximal pyrophosphate accumulation in yeast coincide with those of the minimal contest of polymeric acid-soluble polyphosphates and intense budding. In the light of the data obtained, the question is discussed as to the relationship between the metabolism of pyrophosphates and acid-soluble polyphosphates in yeats.

Adenosine Triphosphate↗
PubMed1981

Protein composition of Bdellovibrio bacteriovorus and Escherichia coli membranes during their interaction.

A comparative study of membrane proteins of Bdellovibrio bacteriovorus and host-bacteria Escherichia coli was performed by polyacrylamide gel electrophoresis in presence of sodium dodecyl sulphate. Infection of E. coli cells by bdellovibrions resulted in the loss of some high-molecular proteins and appearance of new ones in the host-bacteria membranes. The possible role of parasite proteases in degradation of host-bacteria membrane proteins is discussed.

Bacterial Proteins↗
PubMed1981

Multiple forms of alkaline phosphatase from Escherichia coli cells with repressed and derepressed biosynthesis of the enzyme.

Isolation of multiple forms of alkaline phosphatase from Escherichia coli cells with repressed and derepressed biosynthesis of the enzyme is reported. Three enzyme forms were isolated from cells with derepressed synthesis, and one form was isolated from cells with repressed enzyme synthesis. The multiple enzyme forms did not differ in pH optimum, thermostability, or the degree of inhibition with orthophosphate; however, they did differ in the relative rate of hydrolysis of different substrates. The addition of substrates to the cells during enzyme derepression resulted in changes of the ratio of the multiple forms.

Alkaline Phosphatase↗
PubMed1981

[Interrelationship of polyphosphate metabolism and levorin biosynthesis in Streptomyces levoris].

The effect of inorganic phosphate on biosynthesis of the polyene antibiotic levorin by Streptomyces levoris was studied. At phosphate concentration of 4.0 mM levorin biosynthesis is repressed by 90%, resulting in an increase of ATP and a condensed inorganic polyphosphates content in the producer cells. At phosphate concentration optimal for levorin production (0.04 mM) the level of intracellular ATP sharply falls by the beginning of the steady-state phase of the producer growth and that of polyphosphates decreases 3-6-fold. The inorganic phosphate exerts different effects on polyphosphate metabolism enzymes, such as polyphosphate: D-glucose-6-phosphotransferase, polyphosphate phosphohydrolase, tripolyphosphate phosphohydrolase, pyrophosphate phosphohydrolase, alkaline and acid phosphatase. The strongest effect of phosphate excess is observed in the case of polyphosphate: D-glucose-6-phosphotransferase, whose activity decreases 2-5-fold. The activity of this enzyme was shown to be correlated with the antibiotic accumulation. The data obtained are indicative of interrelationship between the polyphosphate metabolism and levorin biosynthesis.

Adenosine Triphosphate↗