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M Tichá

Publications and source records attributed to M Tichá.

7 recordsLinked to original sources
PubMed1979

Studies on lectins. XLIV. The pH dependence of lectin interactions with sugars as determined by affinity electrophoresis.

The pH dependence of association constants of the lectin-sugar complexes was determined by means of affinity electrophoresis. All the lectins studied (from the seeds of Dolichos biflorus, Glycine soja, Lens esculenta and Vicia cracca and of the fruiting body of Marasmius oreades) were characterized by a similar course of pH dependence of the association constants, with the maximum values at pH 7--9. For concanavalin A and the L-fucose binding Ulex europaeus lectin only the association constants at three selected pH values were determined. Concanavalin A does not interact with immobilized alpha-D-mannosyl residues at pH 2.3. The association constants vs. pH curves measured for lectins isolated from two different lentil varieties slightly differ in accordance with the differences observed in the interaction of these lectins with the Sephadex gel.

Binding Sites↗
PubMed1978

Affinity electrophoresis of proteins interacting with Blue dextran.

Interaction of several enzymes (pyruvate kinase, myokinase, creatine kinase, aldolase, malate dehydrogenase, lactate dehydrogenase, alcohol dehydrogenase and glucose-6-phosphate dehydrogenase) and other proteins (bovine serum albumin and ovalbumin) with Blue Dextran was studied by means of affinity electrophoresis in polyacrylamide gels. A decrease of electrophoretic mobility of enzymes in affinity gels was dependent on Blue Dextran concentration and in some cases, dissociation constants of the protein-immobilized dye complexes could be calculated. Affinity electrophoresis in the presence of Blue Dextran reveals in some cases additional bands of isoenzymes, as compared with the control gels (without Blue Dextran).

Alcohol Oxidoreductases↗
PubMed1978

Studies on lectins. XXXIV. The effect of thermal treatment on the lectin of lentil seeds (Lens esuclenta Moench).

The lectin of lentil seeds (Lens esculenta Moench) dissociates into subunits upon incubation of its solution at temperatures above 50 degrees C. The dissociation is accompanied by precipitation of the heavy subunit, release of Mn2+ from the protein molecule and an almost complete loss of erythroagglutinating activity. Addition of Mn2+ or D-glucose to the lectin solutions has a partially protective effect on the dissociation and inactivation.

Glucose↗
PubMed1977

Studies on lectins. XXXI. Determination of dissociation constants of lectin. Sugar complexes by means of affinity electrophoresis.

A modification of affinity electrophoresis in polyacrylamide gels containing immobilized sugar residues is described. The immobilization of sugar residues is achieved by addition of a water soluble O-glycosyl polyacrylamide copolymer to the polymerization mixture, which serves for the preparation of gels for commonly used discontinuous polyacrylamide gel electrophoresis. The electrophoretic mobility of lectins in affinity gels containing specific immobilized sugar decreases with increasing sugar concentration. The addition of free sugar into the affinity gel abolishes retardation of the electrophoretic mobility caused by immobilized sugar. The relationship between electrophoretic mobility of lectins and concentration of immobilized and free sugar was used for the calculation of dissociation constants of the various complexes lectin-immobilized sugar and lectin-free sugar.

Electrophoresis, Polyacrylamide Gel↗
PubMed1977

Studies on lectins. XXXII. Application of affinity electrophoresis to the study of the interaction of lectins and their derivatives with sugars.

Affinity electrophoresis was used to study the sugar binding heterogeneity of lectins or their derivatives. Commercial and demetallized preparations of concanavalin A could be resolved by affinity electrophoresis into three components with different affinity to immobilized sugar. Similarly the Vicia cracca lectin obtained by affinity chromatography behaved on affinity gels as a mixture of active and inactive molecular species. Affinity electrophoresis has shown that the nonhemagglutinating acetylated lentil lectin and photo-oxidized or sulfenylated pea lectin retain their sugar binding properties; dissociation constants of saccharide complexes of these derivatives are similar to those of native lectins. The presence of specific immobilized sugar in the affinity gel improved the resolution of isolectins from Dolichos biflorus and Ricinus communis seeds.

Acetylation↗
PubMed1976

Studies on phytohemagglutinins. XXVIII. Chemical modifications of the lectin from seeds of the lentil (Lens esculenta Moench.)

The reaction of lentil lectin with maleic anhydride yields maleyl derivatives with a degree of modification depending on the amount of used maleic anhydride. Hemagglutinating activity of maleyl derivatives decreases with the increasing number of modified lysine residues, but even at a maleylation of 90% of free -NH2 groups, the maleyl derivative of the lectin still retains a hemagglutinating activity. Maleylation of the lentil lectin is not accompanied by dissociation; the chemically modified lectin also retains its bound Mn. Maleyl derivatives of the lectin retain the ability to interact specifically with polysaccharides (Sephadex, mannan). After removal of maleyl groups in acidic medium, the hemagglutinating activity does not differ from that of the native lectin. Acetylation of the lentil lectin with N-acetylimidazole results in formation of a modified protein containing 3-5 acetylated -OH groups of the tyrosyl residues out of the total of 15 groups and 7-17 acetylated -NH2 groups out of the total of 26 free -NH2 groups, depending upon the reaction conditions. The presence of D-mannose in the reaction mixture does not affect the extent of modification of tyrosyl groups, but it decreases the modification of -NH2 groups. Acetyl derivatives of the lentil lectin do not possess hemagglutinating activity, but they retain the ability to interact with polysaccharides and to bind to erythrocytes. Acetylation does not affect the content of protein bound Mn. After de-O-acetylation, the hemagglutinating activity of the modified protein increases to the value of the native protein.

Acetates↗