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Biomedical subjects

J Turková

Publications and source records attributed to J Turková.

At least 19 recordsLinked to original sources
PubMed1992

Galactosylation as a tool for the stabilization and immobilization of proteins.

This paper presents a brief overview of the role that the carbohydrate moieties of biologically active glycoproteins play in the stabilization and oriented immobilization of these proteins on solid supports. The synthetic galactosylation of hydrophobic areas or their surroundings on the protein surface improves the structural stability of native proteins against inactivation by the interaction of water with hydrophobic clusters. The lowering of the degree solvation of tyrosine residues in galactosylated trypsin and the model substance N-carbobenzoxy-L-glutamyl-L-tyrosine was proved by Raman spectroscopy. D-Galactose residues can be selectively oxidized, either with periodate or enzymatically, and the aldehyde groups thus formed are used for the immobilization of glycoproteins on solid supports with hydrazide groups under mild conditions.

Animals↗
PubMed1990

Carbohydrates as a tool for oriented immobilization of antigens and antibodies.

A biospecific sorbent for the isolation of ovalbumin antibodies was prepared by coupling of ovalbumin via its periodate-oxidized carbohydrate moiety to bead cellulose modified with adipic acid dihydrazide. The anti-ovalbumin IgG fraction isolated on this sorbent from immune rabbit serum contained only antibodies against protein determinants of ovalbumin. Thus, when these IgG were immobilized through their carbohydrate moieties to cellulose beads it became possible to prepare a biospecific sorbent for concanavalin A by oriented adsorption of ovalbumin. Ovalbumin was specifically adsorbed via its protein moiety and its carbohydrate part remained free for interaction with concanavalin A.

Adsorption↗
PubMed1978

Methacrylate gels with epoxide groups as supports for immobilization of enzymes in pH range 3-12.

Glycidyl methacrylate gels are carriers suitable for attachment of enzymes and for use in affinity chromatography. Experiments on the coupling of glycyl-L-leucine and acetyl-L-leucine to these gels have shown a high pH-dependence of the bond formation between the support and the alpha-amino group (pH optimum 9.7); the coupling reaction between the epoxide group and the carboxyl group is practically pH-independent. Serum albumin and trypsin were attached to a greater extent in acidic than in alkaline media. The effects of time and temperature were also studied. The catalytic action of immobilized trypsin, as well as its use for affinity chromatography of trypsin inhibitor, were studied.

Dipeptides↗
PubMed1978

Affinity chromatography of proteases of hydroxyalkyl methacrylate gels with covalently attached inhibitors.

The efficient isolation of trypsin and chymotrypsin from a crude pancreatic extract was achieved by affinity chromatography on specific adsorbents prepared by coupling of both naturally occurring protease inhibitors and also synthetic low-molecular-weight protease inhibitors to hydroxyalkyl methacrylate gels. Specific sorbents prepared with synthetic inhibitors are stable and are suitable for the isolation of chymotrypsin and trypsin even on a large scale.

Chromatography, Affinity↗
PubMed1977

Reactive carriers of immobilized compounds.

Sphericanl macroporous reactive carriers capable of forming covalent bonds with amino acids and proteins were prepared by the suspension copolymerization of 2-hydroxyethyl methacrylate, ethylene dimethacrylate and p-nitrophenyl esters of methacrylic acid and methacryloyl derivatives of glycine, beta-alanine and epsilon-aminocaproic acid. The effect of the spacer length, pH and the type of the buffer used, concentration of reactive groups in the copolymer, concentration of the ligand and the participation of the hydrolytic and aminolytic reaction of p-nitrophenyl functional groups in the attachment of glycine, D,L-phenylalanine and serumalbumin was studied. Macroporous copolymers containing reactive functional groups can be used as active enzyme carriers, if their activity is not blocked by the presence of p-nitrophenol split off in the attachment reaction.

Carboxylic Acids↗
PubMed1976

Affinity chromatography on hydroxyalkyl methacrylate gels. III. Adsorption of chymotrypsin to poly(hydroxyalkyl methacrylates) with covalently bound benzyloxycarbonyl-glycyl-D-phenylalanine and -D-leucine as function of pH and ionic strength.

Chymotrypsin is specifically adsorbed at low ionic strength and alkaline pH to hydroxyalkyl methacrylate gels with N-benzyloxycarbonylglycl-D-phenylalanine or N-benzyloxycarbonylglycyl-D-leucine attached through 1,6-hexanediamine. Chymotrypsin is not adsorbed either to the unmodified gel (Spheron) or to the gel with attached, 1,6-hexanediamine (NH2-Spheron). The adsorption of chymotrypsin to Z-Gly-D-Phe-NH2-Spheron was investigated as a function of pH and ionic strength. Trypsin is not adsorbed to this gel. Chymotrypsin isolated from a crude pancreatic extract by affinity chromatography on Z-Gly-D-Phe-NH2-Spheron had the same activity as the enzyme isolated on a column of Spheron, to which the naturally-occurring trypsin inhibitor had been coupled.

Binding Sites↗
PubMed1976

Isolation of aminopeptidase from Aspergillus flavus.

A mixture of aminopeptidase and neutral protease from the Aspergillus flavus mold obtained by chromatography on DEAE-Sephadex was fractionated by chromatography on the hydroxyalkyl methacrylate gel with chemically bonded 1,6 hexamethylene diamine and D-leucine. Aminopeptidase thus obtained was electrophoretically homogeneous. Conditions for chromatography were worked out allowing a one stage isolation of a highly active aminopeptidase sample directly from the alcoholic precipitate of the culture medium of the Aspergillus flavus mold.

Aminopeptidases↗
PubMed1975

SH-proteinase from bean Phaseolus vulgaris var. Perlicka.

An SH-proteinase (EC 3.4.22.-) has been isolated from beans of the species Phaseolus vulgaris var. Perlicka. The enzyme is homogeneous when subjected to disc electrophoresis, electrofocusing and sedimentation analysis. The molecular weight was determined as 26,000-28,000 by gel filtration, 30,850 +/- 1500 by sedimentation analysis and 26,930-27,410 by calculation from the amino acid composition (Lys20-21, His3, Arg9, Asp21-22, Thr13, Ser18, Pro12-13, Glu23-24, Gly30, Ala16, Cys/29, Val19, Met1, Ile10, Leu13, Tyr14, Phe6, Trp3). The N-terminal amino acid of the proteinase is isoleucine. The effect of concentration, time of hydrolysis, pH, temperature, cations, anions, urea and guanidine - HCl on the proteolytic activity of the SH-proteinase was studied.

Amino Acids↗
PubMed1975

Pepsin immobilized by covalent fixation to hydroxyalkyl methacrylate gels: preparation and characterization.

Insoluble active derivatives of pepsin (EC 3.4.23.1) were prepared by covalent binding of this enzyme to hydroxyalkyl methacrylate gels modified with 1,6-diaminohexane or epsilon-aminocaproic acid in an acid medium by means of water-soluble carbodiimide. The amount of attached enzyme, its proteolytic activity, pH activity curves of the preparations obtained and the time and pH dependence of their stability were determined.

Drug Stability↗
PubMed1975

Affinity chromatography on hydroxyalkyl methacrylate gels. II. Isolation of thiol-containing protein and peptide using mercurial derivatives of gels.

Absorption properties of hydroxyalkyl methacrylate gels containing various amounts of mercuri derivatives of p-acetaminophenoxyethyl methacrylates (Hg-APEMA) and methacrylanilide (Hg-MAA) were investigated by means of a reduced Ellman's agent (5,5'-dithiobis-2-nitrobenzoic acid) and papain. The optimum gel was used for the affinity chromatography of SH-protease from beans and for the isolation of a peptide with a free sulphhydryl group from the chymotryptic hydrolyzate of serum albumin.

Buffers↗