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G Pfleiderer

Publications and source records attributed to G Pfleiderer.

At least 55 records · Page 3Linked to original sources
PubMed1977

[Immunohistochemical localization of creatinkinase isoenzymes in human tissue (author's transl)].

The use of an immunohistochemical method permits the localization of creatine kinase isoenzymes MM and BB in tissue sections. Frozen sections are first incubated with the specific antiserum and secondly with the soluble antigen under investigation. The antibody fixed creatine kinase can then be visualized by the tetrazolium-salt linked histochemical reaction. In this way CK-BB was found in the smooth muscle and the mucosa of the human colon. In sections of skeletal muscle CK-MM was predominantly localized in the intermyofibrillar space. Membrane bound activity could be demonstrated in the sarcoplasmic reticulum and the surface membrane after elution of the cytoplasmic enzyme. In the human tonsilla CK-BB was localized in lymphatic and epithelial tissues, CK-MM in the muscle fibers. The isoenzyme patterns in single sections of tonsilla were in parallel determined by the immunotitration assay. The results indicate the usefulness of the combined application of histochemistry and immunotitration in serial tissue sections.

Colon↗
PubMed1977

Characterisation of a highly hydrophobically modified lactate dehydrogenase.

1. Lysine residues of porcine H4 lactate dehydrogenase (L-lactate:NAD+ oxidoreductase EC 1.1.1.27) were modified with methyl-epsilon-(N-2,4-dinitrophenyl)aminocaproimidate - HCl. With increasing incorporation of the reagent a linear decrease of enzymatic activity was noticed. No essential lysyl group with an extraordinary reactivity was modified. 2. The active forms of the modified enzyme with different incorporation values were separated from denatured material by fractional precipitation and gel chromatography. An epsilon-(N-2,4-dinitrophenyl)aminocaproamidinate lactate dehydrogenase was obtained with an average incorporation of 38 groups per tetramer and a residual activity of 42%. This material proved to be homogenous in cellulose electrophoresis. 3. The epsilon-(N-2,4-dinitrophenyl)aminocaproamidinate lactate dehydrogenase is soluble only in glycine buffer at pH 8 and can be stabilized as ternary complex with NAD+ and sodium sulfite. Gel chromatography and ORD measurements show no strong conformational change. 4. epsilon-(N-2,4-dinitrophenyl)aminocaproamidinate lactate dehydrogenase has similar Km values for pyruvate, NADH, lactate and NAD+ as the native enzyme, and shows a lower thermostability due to a diminished stabilization by the hydrate layer on the surface.

Aminocaproates↗
PubMed1977

The changes in aldolase isoenzyme pattern during development of the human kidney and small intestine--demonstrated in organ extracts and tissue sections.

Aldolases A, B and C were determined by immunotitration analysis in extracts of human kidney and small intestine and demonstrated immunohistochemically in tissue sections of the same organs at various stages of development. By both techniques a change of isoenzyme pattern during development of the kidney and the small intestine was observed, leading from the predominance of A-type towards the predominance of B-type aldolase. In the extracts of kidney and small intestine the specific activity of aldolase B--but not that of aldolase A--rises with age by about one order of magnitude. The histochemical investigation showed that the developmental change in aldolase pattern in the organ extracts is caused by the differentiation of proximal tubulus cells in the kidney and the differentiation of epithelial cells in the small intestine. Within these cells an increase in the concentration of aldolase B and a decrease in that of aldolase A takes place during development. The possible physiological role of this cellular change in aldolase isoenzyme pattern is discussed. Aldolase C was found only in low concentrations in fetal organs. Only in the kidney, a specific localization within the proximal tubules could be demonstrated.

Fetus↗
PubMed1977

The topography of porcine lactate dehydrogenase isoenzyme H4. The identification of lysines on the surface.

Porcine lactate dehydrogenase isoenzyme H4 was treated with methyl 6-(2,4-dinitrophenylamino)hexanimidate hydrochloride and the lysines modified hereby were identified. For this purpose 20 chymotryptic-tryptic N epsilon-[6-(2,4-dinitrophenylamino)hexanimidoyl]lysine containing peptides were isolated by means of gel chromatography, countercurrent distribution, thin-layer chromatography and ion-exchange chromatography. Their amino acid composition, the amino end groups and their electrophoretic mobilities were determined. With these data, the known primary structure of the procine lactate dehydrogenase isoenzyme H4 and the 6-A resolution structure analysis performed by Rossmann et al.[1] we identified the following lysines on the surface of the quarternary structure of the enzyme: no. 4, 6, 60, 77, 82, 121, 157, 179, 226, 230, 241, 306, 308, 316, 327 and 330. No modified lysine peptides were found in the intersubunit binding sites.

Amino Acid Sequence↗
PubMed1976

The synthesis of spin-label derivatives of NAD+ and its structural components and their binding to lactate dehydrogenase.

Spin-labelled derivatives of NAD+ and its structural components (i.e. adenosine, adenine, AMP, ADP and ADPR) have been synthesized. Their binding to pig heart lactate dehydrogenase (L-lactate:NAD+ oxidoreductase, EC 1.1.1.27) has been studied and dissociation constants have been determined. The spin-labelled derivatives of ADP and ADPR exhibit a tighter binding than the corresponding NAD+ derivative. This may be attributed to the repulsion of the positively charged nicotinamide ring by an histidine side chain in the active center of the enzyme.

Animals↗
PubMed1976

A transition state analogue for two pyruvate metabolizing enzymes, lactate dehydrogenase and alanine dehydrogenase.

The synthesis of 5-(2-oxalylethyl)-NADH, a reduced nicotinamide adenine dinucleotide (NADH) derivate with pyruvate covalently attached to the 5 position of the dihydronicotinamide ring over an additional methylene group has been described previously (Trommer, W.E., Blume, H., and Kapmeyer, H. (1976) Justus Liebigs Ann. Chem., 848). In the presence of lactate dehydrogenase, the dihydropyridine ring of this coenzyme-substrate analogue is oxidized and the carbonyl function of the side chain is reduced to the corresponding L-hydroxy derivative with a maximum velocity of 1/3000 of the natural reaction. This reaction is intramolecular as shown by competition experiments with pyruvate. 5-(2-oxalylethyl)-NADH (pyr-NADH) appears to be a true transition state analogue, proving its postulated structure. Pyr-NADH is high specific for this enzyme as demonstrated by the facts that (1) D-lactate dehydrogenase does not catalyze the intramolecular redox reaction, although the substrate moiety of pyr-NADH is reduced in the presence of NADH; (2) when tested with malate dehydrogenase, alcohol dehydrogenase, glyceraldehyde phosphate dehydrogenase,glycerate dehydrogenase, and glycerol dehydrogenase pyr-NADH is not even oxidized in the presence of the corresponding substrates. However, a great similarity between the transition states of the reduction of pyruvate catalyzed by lactate dehydrogenase and alanine dehydrogenase could be shown. Alanine dehydrogenase catalyzes the intramolecular redox reaction as well. In the presence of ammonium ions, pyr-NADH is transformed to 5-(3-carboxyl-3-aminopropyl)-NAD+.

Alanine↗
PubMed1976

Alkaline phosphatase of human and calf small intestine. Purification and immunochemical characterization.

Alkaline phosphatase from human and calf small intestines has been prepared and purified until homogeneous, as judged by polyacrylamide gel electrophoresis, by means of the following techniques: n-butanol extraction, ammonium sulfate precipitation, acetone fractionation, ion exchange chromatography and isoelectric focusing in a sucrose density gradient. Three and two alkaline phosphatase froms from human and calf small intestines, respectively could be isolated by preparative isolectric focusing. The relative amounts of these components are not constant, but they have the same catalytic properties, suggesting that they may embody a common protein core with an identical active centre(s). Precipitating antisera for alkaline phosphatase from human and calf intestine have been prepard in rabbits by intramuscular, dermal, subcutaneous and intravenous administration of the pure major component of each enzyme species. Both antisera precipitate completely their homologous as well as their heterologous antigens (intestinal enzyme) and showed partial identity with placental alkaline phosphatase. There was no reaction with alkaline phosphatase from bone, liver heart, spleen, lung, stomach, pancreas, brain, bile-gall bladder and erythrocytes. Alkaline phosphatase preparation from human kidney contains a minor component of the intestinal type, beside many multiple forms which, on treatment with neuramindase, became identical in their electrophoretic and biochemical properties. At least eight multiple forms of the placental enzyme could be shown by isoelectric focusing in polyacrylamide gel. On treatment with neuraminidase these forms became less charged and only four forms remained. All forms were immunologically identical using either anti placental-enzyme or anti intestinal-AP serum. Monospecific antisera against human or calf intestinal alkaline phosphatase were obtained by absorption with purified placental enzyme. This monospecific anti intestinal-AP serum could be used for an immunological quantitative determination of the intestinal isoenzyme in sera or other liquids in the presence of other alkaline phosphatase isoenzymes.

Alkaline Phosphatase↗
PubMed1975

The cellular distribution of aldolase isozymes in rat kidney and brain determined in tissue sections by the immuno-histochemical method.

The use of the immuno-histochemical method permits the localization of aldolase isozymes in tissue sections. Upon incubating a section with a monomer-specific antiserum, isozymes containing that monomer remain in the section, whereas other cytoplasmic enzymes diffuse out of the section. If soluble antigen is added subsequently, it is bound by the tissue-bound antibody. These antibody fixed aldolases can then be stained by the use of a tetrazolium test linked to substrate hydrolysis. In this way it was demonstrated that isozymes of aldolase containing mostly the A monomer are predominantly localized in the distal tubules, the collecting tubules, the vessels and capillaries of the kidney, the ganglia, the Purkinje cells, the neurons, the white matter and the chorioid plexus of the brain. Aldolase containing mostly B-monomers were found in the proximal tubules. Aldolase isozymes particularly rich in C-monomers were seen in the nervus opticus, the pia mater, the vessels of cerebrum and the molecular layer of the cortex cerebelli.

Brain↗
PubMed1975

On the role of tryptophan residues in the mechanism of action of glyceraldehyde-3phosphate dehydrogenase as tested by specific modification.

A method is described to selectively modify one of the three tryptophan residues of the subunit of glyceraldehyde-3-phosphate dehydrogenase from yeast. As modifying agent dimethyl (2-hydroxy-5-nitrobenzyl) sulfonium bromide was used. The residue which is modified by the procedure described has been identified as Trp-193. There are either one or two molecules of the modifying agent being added to this tryptophan side chain. The modification apparently does not cause a detectable conformational change of the protein as judged from the methods employed. However, the enzymatic activities in the dehydrogenase as well as in the esterase reactions are lost after the modification. It could be established that the modification rendered the enzyme unable to bind the oxidized coenzyme. Also the charge-transfer interaction between enzyme and coenzyme could no longer be observed.

Apoproteins↗
PubMed1975

Quantitation of creatine kinase isoenzymes in human tissues and sera by an immunological method.

Antisera against the crystallized creatine kinase isoenzymes from human skeletal muscle (MM) and from human brain (BB) were produced in rabbits. Both the MM and BB isoenzymes were precipitated quantitatively by their homologous antisera. No cross-reaction was observed. Thy hybrid MB from human heart muscle could not be precipitated completely by either of the two antisera. In artificial mixtures the concentrations of individual creatine kinase isoenzymes were determined from the percentage of non-precipitable activity in the supernatant after reaction with each of the antisera. This immunotitration assay was applied to study the quantitative distribution of creatine kinase compared with those determined by electrophoretic analysis. In sera of patients with myocardial infarction, the immunotitration assay allowed the sensitive and rapid quantitation of creatine kinase isoenzymes, especially of the "infarct-specific" hybrid MB, even in sera with low total activity. This indicates that the method is of diagnostic value.

Animals↗
PubMed1975

Histological examination of the aldolase monomer composition of cells from human kidney and hypernephroid carcinoma.

Aldolase was specifically fixed in tissue sections by the use of antibody prepared either against aldolase A or against aldolase B. The localization of the antigen was demonstrated with the immuno-histochemical method. Aldolase A was found to be the predominant constituent in the cytoplasm of the distal tubules, the large vessels and the glomerula of normal kidney, and aldolase B in the proximal tubules. The collecting tubules and the capillaries contained a mixture of the two types. In the hypernephroid carcinoma cells only aldolase A could be found, but the capillaries within the tumor tissue did contain some aldolase B. Confirmation of these results was obtained by analysis of homogenate prepared with carefully selected tissue parts.

Adenocarcinoma↗
PubMed1975

D-glucose dehydrogenase from Bacillus megaterium M 1286: purification, properties and structure.

1) Glucose dehydrogenase from Bacillus megaterium has been purified to a specific activity of 550 U per mg protein. The homogeneity of the purified enzyme was demonstrated by gel electrophoresis and isoelectric focusing. 2) The amino acid composition has been determined. 3) The molecular weight of the native enzyme was found to be 116000 by gel permeation chromatography, in good agreement with the values of 120000 and 118000, which were ascertained electrophoretically according to the method of Hedrick and Smith and by density gradient centrifugation, respectively. 4) In the presence of 0.1% sodium dodecylsulfate and 8M urea, the enzyme dissociates into subunits with a molecular weight of 30000 as determined by dodecylsulfate gel electrophoresis. These values indicate that the native enzyme is composed of four polypeptide chains, each probably possessing one coenzyme binding site, which can be concluded from fluorescent titration of the NADH binding sites. 5) In polyacrylamide disc electrophoresis, samples of the purified enzyme exhibit three bands of activity, which present the native (tetrameric) form of glucose dehydrogenase and two monomeric forms (molecular weight 30000), arising under the conditions of pH and ionic strength of this method. 6) The enzyme shows a sharp pH optimum at pH 8.0 in Tris/HCl buffer, and a shift of the pH optimum to pH 9.0 in acetate/borate buffer. The limiting Michaelis constant at pH 9.0 for NAD is 4.5 mM and 47.5 mM for glucose. The dissociation constant for NAD is 0.69 mM. 7) D-Glucose dehydrogenase is highly specific for beta-D-glucose and is capable of using either NAD or NADP. The enzyme is insensitive to sulfhydryl group inhibitors, heavy metal ions and chelating agents.

Alcohol Oxidoreductases↗