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G Birkenmeier

Publications and source records attributed to G Birkenmeier.

51 records · Page 3Linked to original sources
PubMed1989

Differences in hydrophobic properties for human alpha 2-macroglobulin and pregnancy zone protein as studied by affinity phase partitioning.

Human alpha 2-macroglobulin and pregnancy zone protein are related with regard to primary structure, physicochemical properties, and quarternary structure. Both proteins undergo conformational changes when they form complexes with proteinases or react with primary amines. The surface properties of the native, chymotrypsin-treated and methylamine-treated forms of alpha 2-macroglobulin and pregnancy zone protein were studied by partitioning in aqueous two-phase systems composed of 7.5% dextran T70 and 5% poly(ethylene glycol) 8000. All proteins and their derivatives had a high potential for hydrophobic interaction as analyzed in terms of affinity for poly(ethylene glycol) esters of fatty acids included in the phase systems. Treatment of alpha 2-macroglobulin with methylamine or chymotrypsin increased the surface hydrophobicity significantly compared to that of the native protein. No difference in hydrophobic interaction was found for native and methylamine-treated pregnancy zone protein, but the chymotrypsin-treated protein showed a marked increase in binding to the hydrophobic ligand. The changes in surface hydrophobicity parallel changes in receptor binding properties of the derivatized forms of alpha 2-macroglobulin and could be a signal for binding to cell-surface receptors, followed by internalization.

Centrifugation↗
PubMed1988

Affinity separation of proteins in aqueous three-phase systems.

Aqueous polymer three-phase systems composed of dextran-Ficoll-polyethylene glycol-water have been used for affinity partition of proteins. The upper, middle, and lower phases are rich in polyethylene glycol, Ficoll, and dextran, respectively. Affinity partition was performed using the reactive dyes Cibacron Blue F36-A and Remazol Yellow GCL which are known as specific ligands for albumin and prealbumin from human serum. When the ligands were bound alternatively to polyethylene glycol, Ficoll, or dextran the target proteins were directed toward the upper, middle, or lower phase, respectively. In the presence of two ligands immobilized to two different polymers the distribution of two proteins could be steered to different phases at the same time. Serum albumin and prealbumin could be separated by using Cibacron Blue-Ficoll and Remazol Yellow-dextran or Cibacron Blue-polyethylene glycol and Remazol Yellow-dextran as polymer ligands.

Albumins↗
PubMed1987

Interaction of the dye Remazol Yellow GGL to prealbumin and albumin studied by affinity phase partition, difference spectroscopy and equilibrium dialysis.

In partition experiments in aqueous two-phase systems composed of 10% (w/w) dextran (Mr = 500,000) and 7.5% (w/w) poly(ethylene-glycol) (Mr = 6,000) prealbumin and albumin are directed into the dextran-rich phase. Addition of Remazol Yellow GGL covalently bound to poly(ethylene-glycol) causes a transfer of prealbumin and albumin into the poly(ethylene-glycol)-rich phase. This indicates an interaction of both proteins with the dye (affinity phase partitioning). The affinity partitioning effect on prealbumin is markedly increased by an excess of monomeric albumin. This points to an interaction of the two proteins in the presence of the dye. Binding of free Remazol Yellow GGL to prealbumin and albumin was investigated by means of equilibrium dialysis and difference spectroscopy. In respect to prealbumin equilibrium dialysis resulted in the binding of four molecules of the dye to two classes of binding sites with dissociation constants of KH = 3.3 microM and KL = 258 microM respectively whereas albumin was found to bind eight molecules of the dye to two classes of binding sites with KH = 5.8 microM and KL = 282 microM. Similar binding stoichiometries were found by difference spectroscopy. By application of difference spectroscopy and affinity phase partitioning thyroxine and triiodothyronine known as natural ligands of prealbumin and albumin were found to compete with Remazol Yellow GGL for the dye binding sites of the proteins.

Affinity Labels↗
PubMed1986

Partition of purified human thyroxine-binding globulin in aqueous two-phase systems in response to reactive dyes.

Thyroxine-binding globulin was isolated from pooled human serum by a two-step method involving affinity chromatography on thyroxine-Sepharose and preparative disc-electrophoresis. The final product was found to be homogeneous by polyacrylamide gel electrophoresis and has a molecular weight of 59,000. Isoelectric focusing resolved the protein into seven bands with isoelectric points ranging from 3.9 to 4.3. The isolated protein showed affinity to a number of different dyes as recognized by affinity phase partitioning. The interaction of the protein with the dye Cibacron Blue F3G-A was found to be strongly competitive with the natural ligand thyroxine.

Albumins↗
PubMed1986

Affinity partitioning: a new approach for studying dye-protein interactions.

Affinity partitioning in an aqueous two-phase system composed of dextran and dye-liganded polyethylene glycol was applied to the investigation of the affinity of phosphofructokinase and glucose-6-phosphate dehydrogenase from baker's yeast, as well as of albumin and prealbumin from human serum to diverse reactive dyes. From the change in the partition coefficient K of the proteins in the two-phase system in the presence and in the absence of the dye-liganded polymer, expressed as delta log K, quantitative data for the maximal extraction power and for the affinity of the proteins to various reactive dyes were obtained. The affinity partitioning effect on prealbumin is markedly increased by an excess of monomeric albumin. This points to an interaction of the two proteins in the presence of the dye, Remazol Yellow GGL. The competitive effect of various natural ligands on binding reactive dyes to proteins can be investigated by means of affinity phase partitioning as demonstrated on phosphofructokinase and prealbumin.

Adenosine Triphosphate↗
PubMed1986

Comparison of the binding of poly(ethylene glycol)-bound fatty acids to human albumin and alpha-fetoprotein studied by affinity phase partitioning.

The interaction of human serum albumin and of alpha-fetoprotein to poly(ethylene glycol)-bound fatty acids is compared using the method of affinity partitioning in an aqueous two-phase system composed of dextran, poly(ethylene glycol) and esters of different fatty acids with poly(ethylene glycol). Albumin was found to be bound to the fatty acid derivatives with higher affinity than alpha-fetoprotein. For both proteins binding occurred in dependence on the chain length of the fatty acids with a maximum for the C14-derivative.

Chemical Phenomena↗
PubMed1984

Affinity chromatography and affinity partition of human serum pre-albumin using immobilized Remazol Yellow GGL. Evidence that albumin increases binding of pre-albumin to the dye.

Pre-albumin was isolated from human serum or plasma by ammonium sulphate fractionation and by chromatography on dye-substituted Sephadex G-100 to a high degree of purity. The interaction of the pre-albumin with the dye Remazol Yellow GGL was studied in more detail by means of affinity partitioning in an aqueous two-phase system composed of dextran and poly(ethylene glycol). In the presence of dye-substituted poly(ethylene glycol) the partition coefficient of pre-albumin increases, indicating an interaction with the dye. Human serum albumin was found to enhance this interaction considerably. A similar effect was also shown by bovine albumin but not by egg albumin.

Ammonium Sulfate↗
PubMed1984

Affinity partitioning of albumin and alpha-fetoprotein in an aqueous two-phase system using poly(ethylene glycol)-bound triazine dyes.

Human albumin and alpha-fetoprotein are partitioned in an aqueous two-phase system composed of 10% (w/w) Dextran and 7.5% (w/w) poly(ethylene glycol). When a small amount of poly(ethylene glycol) is replaced by Cibacron Blue F3G-A-liganded poly(ethylene glycol) the partition coefficient, K, of albumin increases by the factor of about 4000 whereas the K value of alpha-fetoprotein undergoes only a small change. The change of the partition coefficient in a logarithmic scale induced by increasing dye-polymer concentrations turned out as a useful measure for the affinity of albumin and alpha-fetoprotein to the dyes. The effect of pH and salt concentration on the affinity partition of albumin and alpha-fetoprotein is demonstrated. The partition of the two proteins in presence of Cibacron Blue F3G-A-liganded poly(ethylene glycol) is compared with seven other triazine dye-poly(ethylene glycol) derivatives.

Charcoal↗
PubMed1983

Triazine dye binding of human alpha-fetoprotein and albumin.

Column chromatography was used to investigate the interaction of human alpha-fetoprotein and albumin with different immobilized dyes. Binding of alpha-fetoprotein to the dye conjugates was studied at pH 7.0. Between 56 and 93% of the total alpha-fetoprotein applied to the column was recovered in the break-through fractions of the respective runs. Of all the dyes, Cibacron Blue F3G-A adsorbs alpha-fetoprotein most strongly. This interaction clearly depends on the degree of dye substitution of the gel. A relatively weak interaction exists between alpha-fetoprotein and immobilized Procion Red HE-3B. This is used in the purification of alpha-fetoprotein by negative chromatography resulting in a 16.6-fold enrichment of this protein. Human albumin binds tightly to immobilized Cibacron Blue F3G-A as well as to Cibacron Brilliant Blue FBR-P and shows a lower affinity to Procion Blue MX-R. Procion Red dyes, which are structurally different from Cibacron Blue F3G-A are also capable of interacting with serum albumin. The results obtained are discussed in terms of the present theoretical conceptions about dye-protein interactions.

Coloring Agents↗
PubMed1982

Application of dye-ligant chromatography to the isolation of alpha-1-proteinase inhibitor and alpha-1-acid glycoprotein.

Various Cibacron blue F3G-A substituted Sephadex G-100 gels which differ in the density of the bound dye were investigated for their applicability in the affinity chromatography of human serum proteins. Protein adsorption was found to depend strongly on the density of the covalently attached dye and on the pH of the applied buffer. A high degree of dye substitution of the gel caused binding of most of the serum proteins. Only a small number of proteins were found to appear in the breakthrough fraction. On this basis a simple and relatively mild procedure for the isolation of homogeneous alpha-1-proteinase inhibitor and alpha-1-acid glycoprotein from human serum was developed. Isolation of alpha-1-acid glycoprotein succeeded in only a single step, whereas that of alpha-1-proteinase inhibitor required two additional steps: a prior ammonium sulphate precipitation and a chromatographic step on DEAE-cellulose at pH 6.5.

Blood Proteins↗
PubMed1976

[Protein-analytical studies on the serum and urine of patients with visceral lupus erythematosus].

Serum and urine of patients with ascertained lupus erythematodes visceralis were separated by means of the polyacrylamide gel pore gradient electrophoresis on the same experimental conditions. Deviations from the normal electropherogram were found in the serum within the gamma-globulins. For the demonstration of antinuclear factors the loose body test, the LE-cell test as well as the immunofluorescence test were carried out. In the uropherogram a highly molecular protein band could be proved which did not appear in the serum. In this fraction an immune complex which developed in the area of the kidney might be in question. It is referred to the possibility of the use of the PAA-polyacrylamide gel electrophoresis for the early recognition of renal changes.

Antibodies, Antinuclear↗
PubMedDate not supplied

Epitope mapping of a monoclonal antibody directed against the alpha-subunit of phosphofructokinase-1 from Saccharomyces cerevisiae by screening phage display libraries.

Phosphofructokinase-1 from Saccharomyces cerevisiae is composed of two types of subunits, alpha and beta. Subunit-specific monoclonal antibodies were raised to elucidate structural and functional properties of both subunits. One monoclonal antibody, alpha-F3, binds to an epitope either at the C-terminal or at the N-terminal part of the alpha-polypeptide chain. By screening a heptapeptide library with this monoclonal antibody, a set of heptapeptides was selected, which contained the consensus sequences D-A-F and D-S-F. Two heptapeptides with these motifs were synthesized in order assess their capacity to inhibit the binding of antibody alpha-F3 to native phosphofructokinase-1. The peptide G-I-K-D-A-F-L inhibited the binding more strongly (IC50 = 1.5 microM) than the peptide A-P-W-H-D-S-F (IC50 = 33.3 microM). Sequence matching revealed the presence of the D-A-F motif in the polypeptide chain of phosphofructokinase-1 at amino acid position 172-174. As a control, the nonapeptide A-P-T-S-K-D-A-F-L which corresponds to the sequence of the putative epitope was tested in the inhibition assay. In view of the high inhibitory capacity (IC50 = 0.3 microM) it was concluded that this nonapeptide represents the continuous epitope of phosphofructokinase-1 that is recognized by antibody alpha-F3.

Antibodies, Monoclonal↗