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I S Kulaev

Publications and source records attributed to I S Kulaev.

At least 55 records · Page 3Linked to original sources
PubMed1994

[A prosegment of the yeast alpha-factor controls a heterologous protein (human growth factor) in Saccharomyces cerevisiae culture media].

The role of the yeast pheromone prosegment--alpha-factor--in the export of the heterologous protein, the human growth hormone (hGH), in the culture medium of S. cerevisiae has been studied. Using genetic engineering constructions, it has been shown that different N-terminal signal peptides (SP) are not able to provide the hGH export. Transformant cells carrying the plasmid with a hybrid sequence encoding the prosegment-hGH (without SP) accumulate non-glycosylated pro-hGH in the cytosol. Only the combination of SP and the prosegment as the N-terminal fragment of the hGH precursor results in the processing and export of the mature form of the hormone. The origin (or type) of SP is of no significance. The glycosylation inhibitors--2-deoxy-D-glucose and tunicamycin--suppress the export but not the entry of hGH into the periplasm, thus indicating a critical role of the intactness of the prosegment polymannose chains for the efficient export of heterologous protein. A conclusion is drawn that the two preprosegment parts play different roles. The SP constituent of prepro-hGH introduces pro-GH into the general secretory pathway, while the prosegment resulting from the SP cleavage directs hGH from the cell into the culture medium.

Amino Acid Sequence↗
PubMed1994

[Characteristics of polyphosphatase activity of Saccharomyces cerevisiae cytosol].

The cytosol fraction purified from cellular organelles was obtained from S. cerevisiae yeast cells. This cytosolic fraction contained a polyphosphatase activity comprising nearly 65% of such in the protoplast homogenate. The pH optimum of this activity was 6.5-7.5. Bivalent metal cations stimulated the polyphosphatase activity 9-14-fold in the following order: Zn2+ > Co2+ > Mg2+, Mn2+. Fe2+, Cu2+ and Ca2+ ions inhibited this activity at all concentrations used. The cytosolic polyphosphatase was effectively inhibited by molybdate and heparin. Heparin was effective only in the presence of Mg2+, Mn2+ and Co2+ but had no effect in the presence of Zn2+. Heparin inhibited polyphosphatase competitively. The polyphosphatase activity was the same with poly (P)9-poly (P)208. On poly (P)9, poly (P)15 and poly (P)208 the Km(app) values were equal to 19, 11, 1.2 microM, respectively. The molecular mass of cytosolic polyphosphatase determined by gel filtration on Sephacryl S-300 was 50 kDa.

Acid Anhydride Hydrolases↗
PubMed1994

[Proteinases with various substrate specificities in structural studies of yeast cell walls].

Different proteins are revealed in cell wall of yeast cells Candida utilis by means of specific proteolysis with subtilisins TV and 72, trypsin and purified collagenase of Clostridium histolyticum. Some of them were characterized by resistance to trypsin and sensitivity to subtilisin TV. In young cells this group is represented essentially by a protein of 33 kD, which appears to be one of the structural proteins, binding fibrillae of carbohydrate. Other proteins proved to be sensitive to both trypsin and subtilisin. Among these proteins a protein with mol. mass 80 kD was revealed; its sensitivity to extremely specific hydrolysis by bacterial collagenase suggests it to contain amino acid sequences characteristic for collagens of higher eukaryotes.

Amino Acid Sequence↗
PubMed1994

[The effect of PAF, sphingosine and heparin on certain phosphohydrolase and transport activity of yeast vacuoles].

The effects of some protein kinase effectors on phosphohydrolase and transport activities of yeast vacuoles have been studied. The platelet-activating factor (PAF), a plant vacuolar protein kinase C stimulator, had a protonophoric and membrane-damaging effects on yeast vacuoles and inhibited the ATP-dependent delta mu H+ formation and ATP-dependent secondary transport but stimulated the ATPase and pyrophosphatase hydrolase activities by abrogating proton control. PAF increasing the tonoplast permeability for the corresponding substrates also stimulated pyrophosphatase, polyphosphatase and alkaline phosphatase activities. Lysolipid sphingosine, a plant vacuolar protein kinase C inhibitor, poorly stimulated the ATPase activity and the ATP-dependent formation of Em in isolated yeast vacuoles, while the pyrophosphatase activity increased by 200%. Other hydrolase activities tested were insensitive to the effect of the lysolipid. Sphingosine inhibited the ATP-dependent citrate transport only insignificantly. Heparin, an effective casein kinase inhibitor, suppressed the ATPase and polyphosphatase activities in isolated yeast vacuoles. The polyphosphatase activity was inhibited both in the vacuolar sap and the tonoplast solubilized by a Zwittergent TM-314, in contrast with the ATPase activity which was inhibited by heparin only in isolated vacuoles. Heparin is suggested to inhibit polyphosphatase by directly influencing the enzyme.

Adenosine Triphosphatases↗
PubMed1993

Analysis of Candida utilis genomic DNA, homologous to cDNA of chicken A1(1) collagen gene.

Genomic fragments, homologous to chicken A1(1) collagen cDNA encoding triple-helical domain, were revealed by Southern analysis in various fungi. Such a genomic fragment from Candida utilis was cloned and sequenced. Analysis of the obtained DNA sequence revealed the 119 bp segment, which has possibly originated from the 54 bp module common for the fibrillar collagen genes of higher eukaryotes.

Animals↗
PubMed1993

Solubilization and characterization of dehydrodolichyl diphosphate synthase from the yeast Saccharomyces carlsbergensis.

When the membrane fraction of Saccharomyces carlsbergensis was incubated with radiolabeled isopentenyl diphosphate in the presence of farnesyl diphosphate and Mg2+, phosphorylated and free long-chain polyprenols were formed. The reaction was inhibited by EDTA and heavy metal cations. A series of non-ionic detergents were studied for their efficacy to solubilize the prenyltransferase. The enzyme completely lost its activity in the presence of 0.1% of Triton X-100. n-Octyl-beta-(D)glucopyranoside at the concentration of 0.25-0.5% (10-15 mM) was used to solubilize the prenyltransferase. Both the membrane-bound enzyme and the solubilizate possessed a broad pH optimum shifted to alkaline pH values. The temperature optimum of the solubilizate was somewhat lower than that of the membrane preparation, owing to the significantly lower thermostability of the solubilized enzyme in comparison with the membrane-bound one. The phosphorylated reaction products formed in the presence of the membrane preparation had the same composition as the yeast dolichol synthesized in vivo. Non-phosphorylated polyprenols were formed during the incubation with membranes but not the solubilized enzyme. The composition of the polyprenols was also coincident with that of yeast dolichol, and the individual C80-homolog of the mixture was polyprenol but not dolichol as judged by adsorption HPLC. The results are discussed in relation to the terminal stages in the biosynthesis of dolichol derivatives.

Alkyl and Aryl Transferases↗
PubMed1993

[A lysoamidase bacteriolytic complex. 1. Determination of the nature of interaction of enzymes and the polysaccharide, included in the complex].

The polysaccharide component of the bacteriolytic enzymatic complex "lysoamidase" (M(r) 1300 kDa) has been found to contain negatively charged ionic groups and can electrostatically interact with some enzymes within the complex. At pH 8.0 optimal for bacterial lysis, such interaction promotes the stabilization of bacteriolytic enzymes, increasing their half-inactivation temperature by 8 degrees and their stability upon storage by 40%. The polysaccharide decreases the thermal stability of phosphatase but has no stabilizing effect on the metalloprotease.

Anti-Infective Agents↗
PubMed1992

Identification of a novel secreted glycoprotein of the yeast Saccharomyces cerevisiae stimulated by heat shock.

A new secreted yeast glycoprotein with an Mr of about 400 kDa (gp400) has been found. The glycoprotein is an O-mannosylated oligomer, whose synthesis and export into culture medium are stimulated by heat shock. Intracellular transport of gp400 is carried out by membrane vesicles distinct from the known constitutive secretory vesicles. Immunological analysis revealed gp400 only in Saccharomyces species.

Amino Acids↗
PubMed1991

Isolation, structural and functional characterization of Staphylococcus aureus protoplasts obtained using lysoamidase.

The action of the lysoamidase bacteriolytic complex on Staphylococcus aureus VKM B-209P cells has been studied to obtain protoplasts. The cells in the midlogarithmic phase were the most sensitive to lysoamidase action. It led to local destruction of cell wall due to hydrolysis of the peptidoglycan. Protoplast formation occurred in two steps in the presence of 1 M sucrose. First, osmotically fragile spheroplasts were formed. Then, the protoplasts were released from the destructed cell wall. The protoplast yield was about 80%. The protoplasts preserved the intact ultrastructure and were able to synthesize peptidoglycan fibrillae. Mainly the spheroplasts that maintained the cell-wall residues reversed into bacterial forms. The protoplasts had respiratory activity similar to cells. Respiration of cells and protoplasts was stimulated by various substrates. High rates of oxygen consumption were observed with alpha-glycerophosphate and ethanol as substrates.

Cell Wall↗
PubMed1991

[Localization of acid phosphatase in Saccharomyces cerevisiae and its export into culture media depends on the type of the N-terminal signal peptide].

The aim of this work was to study the character of intracellular distribution and efficiency of yeast acid phosphatase export depending on the type of the N-terminal signal peptide used. A number of plasmids carrying the acid phosphatase genes with different signal peptides sequences was constructed. The main site of the enzyme accumulation for the variant containing its own acid phosphatase signal peptide was the periplasm. Approximately the same pattern was observed when the hybrid signal peptide consisting of acid phosphatase signal peptide and alpha-factor preprosegment tandem was used. Unlike the above-mentioned systems the strain carrying acid phosphatase under the control of alpha factor preprosegment was able to export the enzyme into the culture medium. The experiments have shown the possibility of changing the final localization of secretory proteins by replacing the N-terminal signal peptide.

Acid Phosphatase↗
PubMed1990

[Hydrolysis of a Staphylococcus aureus cell wall peptidoglycan by 209 P lysoamidase].

Hydrolysis of Staphylococcus aureus 209 P cell wall peptidoglycan was accompanied by the liberation of 1.3 mol of C-terminal and 1.2 mol of N-terminal glycine per mole of Glu as well as of 0.5 mol of N-terminal and 0.3 mol of C-terminal alanine. Gel chromatography on Sephadex G-25, ion-exchange chromatography on QAE-Sephadex A-50 and paper electrophoresis of S. aureus peptidoglycan hydrolysates gave seven homogeneous fractions; these fractions were structurally defined. Lysoamidase hydrolyzed bonds Mur-Ala, Gly-Gly and Mur-GlcN in the peptidoglycan molecule. Hydrolysis of glycan chains was accompanied by the formation of large fragments, (GlcN-Mur)9 and (GlcN-Mur)28. The lytic effect of lysoamidase on S. aureus peptidoglycan is coupled with bacteriolytic enzymes of lysoamidase: acetmuramyl amidase, glycyl--glycine endopeptidase and acetyl--muramidase.

Amino Acid Sequence↗
PubMed1990

[Various physico-chemical and kinetic properties of metalloproteinase from bacteriolytic lysoamidase preparation].

The amino acid composition of metalloproteinase was determined. It was shown that the enzyme is made up of four cysteinyl residues which makes it distinct from other known neutral metalloproteinases from Bacillus brevis, Bacillus subtilis and thermolysine that are devoid of cysteinyl residues. The inhibiting effect of amino acids and some di- and tripeptides on the metalloproteinase activity was studied. The pH-dependence of the Michaelis constant (pKm0) of native and diethylpyrocarbonate-modified metalloproteinase (pKm) suggests that the enzyme active center contains two imidazole groups of histidine with pK alpha 1 = 6.75 +/- 0.1 and pK alpha 2 = 5.4 +/- 0.1. The experimental results are compared to those obtained with other microbial metalloproteinases.

Amino Acids↗
PubMed1989

[Study of the inhibition of neutral phosphatase from Pseudomonadaceae by derivatives of its substrates].

The inhibition of neutral phosphatase isolated from the bacteria of the Pseudomonadaceae family by various fragments of the enzyme-hydrolyzed R-O-PO3H2 substrates, inorganic orthophosphate (KH2PO4) and its analogs as well as by adenine, adenosine, alcohols, sugars and amino acids, was studied. It was demonstrated that among other compounds tested only the orthophosphoric acid anions (H2PO4-) exhibit the properties of strong associative inhibitors (K1Vi = 4.35.10(-6)M of the enzyme. The pH dependence of the Michaelis constant [pKm0 = f(pH)] and the inhibition constant for phosphatase by potassium orthophosphate [pK1Vi(KH2PO4) = f(pH)] was studied. The presence in the enzyme active center of a carboxylic (pK = 4.3 +/- 0.1) (presumably, glutamine) and an imidazole (pK = 7.15 +/- 0.1) amino acid residues was postulated. The data obtained were compared to those for neutral, alkaline and acid phosphatases.

Alcohols↗
PubMed1989

[The components of the microbial preparation of lysoamidase from the Pseudomonodaceae family responsible for its bacteriolytic activity].

The contribution of enzymes isolated from the microbial enzymic preparation to its total bacteriolytic activity was studied. The combined action of the lytic proteinase L2 and the lytic fraction L1 used in the same ratio as in the lysoamidase preparation resulted in a complete recovery of the bacteriolytic activity. During a 4-fold increase of the proportion of the lytic enzyme L1 as compared with lytic proteinase L2, the activity of the reconstituted preparation increased by 64%. Neutral phosphomonohydrolase, metal proteinase and the polysaccharide isolated from the lysoamidase preparation had no effect on the bacteriolytic activity of the reconstituted preparation. The polysaccharide isolated from lysoamidase increased the thermal stability of the preparation obtained up to that of lysoamidase.

Bacteriolysis↗
PubMed1987

Subcellular localization of enzymes in Streptomyces aureofaciens and its alteration by benzyl thiocyanate. I. Phosphatases and ATP-glucokinase.

Mycelia of a low- and a high-production strain of Streptomyces aureofaciens were converted into protoplasts and divided into five subcellular fractions in order to localize exopolyphosphatases (EC 3.6.1.11), triphosphatase (EC 3.6.1.25), inorganic diphosphatase (EC 3.6.1.1), apyrase (EC 3.6.1.5) and glucokinase (EC 2.7.1.2). The highest specific activity of enzymes hydrolyzing polyphosphates was found in cytoplasmic vesicles and membranes. Triphosphatase was detected in the periplasmic fraction. Periplasmic vesicles and cytoplasm exhibited a high activity of diphosphatase. Apyrase was found mainly in the fractions of membranes and cytoplasmic vesicles. Glucokinase was a cytoplasmic enzyme. The enzymes were released from membrane structures into cytoplasm or periplasmic space if benzyl thiocyanate (10 microM) was present in the growth medium.

Cations↗