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Biomedical subjects

H Rüdiger

Publications and source records attributed to H Rüdiger.

At least 55 records · Page 3Linked to original sources
PubMed1980

Interindividual comparison of epoxide hydratase and glutathione S-transferase activities in cultured human fibroblasts.

Epoxide hydratase activity with benzo[a]pyrene 4,5-oxide and glutathione S-transferase activity with 2,4-dinitrochlorobenzene as substrates were determined in cultured fibroblasts from skin biopsies of different donors and from several biopsies of the same donor. Variation of the results from experiment to experiment was reduced by the use of a reference cell strain and expression of the results as activities relative to those of the reference cells. Epoxide hydratase activity varied 2.3-fold in 39 cultures from the same subject (the variation coefficients were 0.22 and 0.15, respectively). The results indicate that, at least in skin fibroblasts, genetically caused interindividual differences in epoxide hydratase activities do not exist or are negligibly small or very rare. Glutathione S-transferase activity varied more in cultures from different donors (variation coefficient = 0.22) than in different cultures from the same donor (variation coefficient = 0.08), but the highest and the lowest activities only differed by a factor of 2.3. No significant differences in either enzyme activity were observed between males, females, subjects without tumours, lung carcinoma bearers and melanoma patients.

Adult↗
PubMed1980

Purification and chemical characterization of the vitamin-B12-dependent 5-methyltetrahydrofolate: homocysteine methyltransferase from Escherichia coli B.

The transferase was isolated by means of hydrophobic chromatography and combination of ion-exchange and gel filtration at different pH values and ionic strengths. As judged by disc electrophoresis, the enzyme is homogeneous. Electrophoresis in the presence of sodium dodecylsulfate reveals only one band with Mr = 49500 +/- 10%. In gel filtration the native enzyme has a Mr of 200,000. The subunits can be crosslinked by iminothiolane followed by hydrogen peroxide oxidation. In sodium dodecylsulfate electrophoresis this results in a band pattern of integer multiples of 50,000 up to 20,000 but not higher. The high-Mr aggregates disappear on splitting the crosslinks by reduction. Thus the enzyme appears to be composed of four subunits identical or nearly identical in Mr. By the dansyl method, only phenylalanine and methionine were found as the amino-terminal residues, suggesting the existence of two different types of subunits.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed1979

Lectin-associated proteins from the seeds of Leguminosae.

The seeds of Pisum sativum (pea), Canavalia ensiformis, Vicia faba, Vicia sativa, and Ricinus communis were shown to contain proteins which are associated to the respective lectins (lectin binders). The lectin binders from Pisum sativum and Canavalia ensiformis were studied more closely. Both are single proteins not resembling the variety of membrane glycoproteins found in animals and plants which bind to lectins. The pea lectin binder is a tetrameric glycoprotein composed of identical subunits of the Mr 51 000. Its interaction with the lectin is abolished by acidic buffers or by glucose. The Concanavalin A binder, which does not contain sugar, is composed of one kind of subunit, Mr of 35 000. As in the case of the pea lectin binder, glucose and acid dissociate the lectin-lectin binder complex, but in contrast to the pea lectin binder low NaCl concentrations also cause this effect. During germination and growth, the Concanavalin A binder appears in the roots.

Concanavalin A↗
PubMed1979

Purification and characterization of a mitogenic lectin and a lectin-binding protein from Vicia sativa.

From the seeds of Vicia sativa, a novel mitogenic lectin was isolated. Purification was carried out by affinity chromatography on Sephadex G-100. The tetrameric lectin is a glycoprotein with a molecular weight of Mr 40 000; it consists of two large beta-subunits (Mr 14 000) and two small alpha-subunits (Mr 6000). The N-terminal sequence of both subunits and their amino acid compositions were determined. The lectin agglutinates human erythrocytes, preferring group B, and erythrocytes from rabbits and horses; no agglutination takes place with sheep erythrocytes. Agglutination is inhibited by mono-, di- and tri-saccharides with the configuration of glucose at the free 4-hydroxyl group. The lectin stimulates mitosis in lymphocytes of mice. From the seeds of the same plant, a protein was isolated which binds to the lectin described above. The lectin binder consists of subunits with a molecular weight of 53 500.

Amino Acid Sequence↗
PubMed1978

[Lectins, sugar-binding plant proteins].

Lectins are proteins which can bind to the surfaces of animal and human cells. They are widespread in the plant and animal kingdom. Though many lectins have been isolated and characterized, and though some are extensively used as cell surface "tools", their biological role is only subject to hypotheses.

Animals↗
PubMed1977

Purification and properties of blood-group-specific lectins from Vicia cracca.

The lectins from the seeds of Vicia cracca react specifically with human blood group A erythrocytes. They were purified by affinity chromatography on an adsorbent containing matrix-bound N-acyl-D-galactosamine. By a continuous pH gradient the lectins could be separated into two fractions each of which was shown to consist of several agglutinating species. The behaviour of both fractions in affinity chromatography was paralleled by the pH dependence of the interaction with the hapten sugar N-acetyl-D-galactosamine. Both lectin fractions have the same molecular (125000) and subunit (33000) weights, display the same pH dependence of their titre against A1 erythrocytes, and bind to N-acetyl-D-galactosamine at pH 8 with the same constant of about 6 X 10(3)M-1.

ABO Blood-Group System↗
PubMed1977

[Purification and properties of the tetrahydropteroylglutamate methyltransferase from green beans (Phaseolus vulgaris) (author's transl)].

The tetrahydropteroylglutamate methyltransferase from green beans (Phaseolus vulgaris) has been purified 80-fold by ion exchange chromatography and gel filtration. Optimal methyl transfer is found at pH 6.5 and 39 degrees C. Even at 0 degrees C, however, a considerable catalytic rate is observed. The Michaelis-Menten constants for homocysteine and 5-methyltetrahydropteroylglutamate are 0.43mM and 2.4 mM, respectively. Magnesium ions enhance the activity. Even purified preparations appear to contain traces of magnesium ions firmly bound, since a residual activity is found without addition of magnesium salts. Though the reaction requires anaerobiosis, an excess of reducing agents is inhibitory. The molecular weight of the transferase, determined by gel filtration, is 40 000 +/- 6%.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗