Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.3.5.1 (succinate dehydrogenase)
 8,177 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Leupeptin (acyl peptidyl-L-argininal) is a potent inhibitor of trypsin and related proteases. We analyzed the association of leupeptim with bovine trypsin kinetically, assuming that it proceeds by a pathway which involves two steps: E + I in equilibrium K1 Complex I k-2 in equilibrium k+2 Complex II. The observed dissociation constant (K1) for the first step was 1.24 X 10(-3) M (at pH 8.2 15 degrees C) and the two first-order rate constants (k+2 and k-2) were 166 s-1 and 1.75 X 10(-3.s-1, respectively (at pH 8.2, 15 degrees C). The dissociation constant (Kd) for the whole process was calculated from these parameters to be 1.34 X 10(-8) M. This value is compatible with that determined directly by an independent static method (2.36 X 10(-8) M). We also measured Kd for the leupeptine complex of anhydrotrypsin, a trypsin derivative in which the active-site hydroxyl group is missing. The observed value was about 5 orders of magnitude larger than Kd and was rather similar to K1 in native trypsin. A elupeptin isomer which contains a D-argininal residue did not show strong affinity towards trypsin. These findings suggest that complex II consists of a covalent hemiacetal adduct formed between the serine hydroxyl group in the enzyme active site and the aldehyde group in the inhibitor. The pH dependencies of the dissociation constant and other parameters show that deprotonation of the charge-relay sustem in the active site is important for the formation and stabilization of complex II.
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PMID:Mechanism of association of a specific aldehyde inhibitor, leupeptin, with bovine trypsin. 57 67

The paper deals with studying the effect of vitamin A deficit in the rat organism on the incorporation of the C14-labelled asparaginic acid serine-3-C14 and glycine-2-C14 into different fractions of skin proteins, with determining the content of glycine cycle components (glycine, glycolic acid and glycolic aldehyde), activity of phosphatases and succinate dehydrogenase in the skin as well as the quantity of mucopolysaccharides and seromucoids in the skin and blood serum. It is established that with vitamin A deficit the intensity of the incorporation of labelled asparaginic acid and serine into the skin total proteins decreases and the incorporation of glycine-2-C14 into the total proteins and the fraction of soluble non-collagen proteins of skin increases. The intensity of the incorporation of the labelled asparaginic acid into the skin soluble collagen falls by 40% but almost twice as high into the soluble non-collagen proteins. A 47% decrease of glycine, 22% fall of glycolic acid and almost two-fold increase of glycolic aldehyde are observed in the skin of the animals with A-avitaminosis. Skin extracts manifest a higher activity of alkaline and acid phosphatases, but a lower activity of succinate dehydrogenase in comparison with control.
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PMID:[Some peculiarities of skin metabolism with vitamin A deficit]. 120 63

Incubation of aldehyde dehydrogenase-free mitochondrial preparations with biogenic amines serotonin, tyramine, 2-phenylethylamine and 5-methoxytryptamine resulted in inhibition of enzymes activity of both outer (rotenone-insensitive NADH-cytochrome c reductase) and inner (succinate dehydrogenase, succinate cytochrome c reductase) mitochondrial membranes. Solubilization of mitochondria after the incubation did not influence the amine-induced alteration of succinate dehydrogenase activity. Pretreatment of the organelles with a mixture containing chlorgyline and deprenyl completely inhibited monoamine oxidase (MAO) activity and prevented the effects of all the amines studied on mitochondrial enzymes. MAO-dependent effects of 5-methoxytryptamine were fully reproduced by 5-methoxyindolyl-3-acetaldehyde (one of probable products of 5-methoxytryptamine deamination). The effect of the aldehyde was not prevented by chlorgyline and deprenyl. After selective inhibition of MAO-A by chlorgyline the order of MAO-B-dependent effects of biogenic amines on mitochondrial enzymes studied was as follows: tyramine greater than or equal to 2-phenylethylamine much greater than serotonin. In deprenyl pretreated mitochondria the potency of MAO-A-dependent effects of these amines was: serotonin greater than tyramine much greater than much greater than 2-phenylethylamine. The data obtained suggest that the product(s) of oxidative deamination of biogenic amines (probably the aldehydes) catalyzed by both types of MAO (MAO-A and MAO-B) are able to regulate the energy functions of mitochondria.
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PMID:[The role of monoamine oxidase in the regulation of mitochondrial energy functions]. 175 90

Young adult Wistar rats received 40 mg/kg of cyclosporin perorally for 21 days. Cyclosporin induced almost total disappearance of thymic medulla, whereas the cortex remained preserved. Although the density of cortical macrophages did not change significantly, their characteristics altered markedly and they became enlarged and rounded. In addition to an increase in acid phosphatase and nonspecific esterase activities, cortical macrophages developed very strong succinic dehydrogenase and chloroacetate esterase activities and a fine, granular, aldehyde fuchsin-positive cytoplasmic content. However, these cytoplasmic granules were PAS-negative and were not sudanophilic. Cortical macrophages retained their normal antigenic properties (which were studied by the use of ED1, ED2 and R-MC 41 monoclonal antibodies). Phagocytic cells in the remaining medullary islands retained their usual characteristics. The changes in cortical macrophages after cyclosporin treatment are discussed, especially in relation to the characteristics of macrophages of the cortico-medullary zone in the normal rat thymus.
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PMID:Macrophages of the rat thymus after cyclosporin treatment. Histochemical, enzymehistochemical and immunohistochemical study. 256 84

Secondary lymphoid follicles in peripheral lymphoid organs (parathymic, mesenteric and inguinal lymph nodes and spleen) from young adult Wistar rats of both sexes were studied. Different numbers of tingible body macrophages containing aldehyde fuchsin-positive cytoplasmic granules of varying size, were present in the germinal centers. An identical staining pattern to that obtained with aldehyde fuchsin in terms of the number, distribution and size of positive cells was seen after staining for succinic dehydrogenase.
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PMID:Succinic dehydrogenase activity in germinal center macrophages in peripheral lymphoid organs of the rat. 288 60

The cortex and medulla of the normal rat thymus are populated with scattered cells which are strongly positive for acid phosphatase and only weakly (cortex) or moderately (medulla) positive for nonspecific esterase. Corticomedullary zone is characterized, as a specific entity within the thymic tissue, by the presence of very large macrophages, highly positive for acid phosphatase and nonspecific esterase. Moreover, these cells, located exclusively in the corticomedullary zone, show very strong succinic dehydrogenase activity and contain the intracytoplasmic granules of varying size, which are aldehyde fuchsin, PAS, and oil red O positive. The presence of cholesterol was demonstrated within the lipid content.
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PMID:Enzyme-histochemical characterization of macrophages in the rat thymus, with special reference to metallophilic cells of the corticomedullary zone. 620 53

The acute effects of ethanol on the nervous system are thought to be associated with disturbance of neural membrane function. In the present study the effects of ethanol, its immediate metabolite, acetyldehyde, and tertiary butanol which is not further metabolized to an aldehyde, on selected membrane-bound enzymes were examined in vitro in rat brain. The enzymes included acetylcholinesterase, succinate dehydrogenase, Na+K+-ATPase and cytochrome c oxidase. At concentrations ranging from 0.07 - 2% w/v (15 - 435 mM) ethanol did not produce significant inhibition of any of the enzymes tested. On the other hand acetaldehyde at concentrations ranging from 0.01 - 0.5% w/v (2 - 114 mM) showed marked inhibition of all the abovementioned enzymes except acetylcholinesterase. The responses of the various enzymes to tertiary butanol were intermediate between those obtained with ethanol and acetaldehyde. Further studies are in progress to evaluate the significance of these findings to the understanding of alcohol intoxication, tolerance and dependence in man.
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PMID:Effect of ethanol and acetaldehyde on membrane-bound enzymes in rat brain. 742 41

The PutA protein of Escherichia coli has two enzymatic activities: proline dehydrogenase (PDH) and delta 1-pyrroline-5-carboxylate dehydrogenase (P5CDH). It associates with the cytoplasmic membrane as PDH and P5CDH and with put control region DNA as put repressor. Reduction of the PutA flavin by proline, a PutA conformational change and association of PutA with membranes are coincident. The nucleotide base sequence of E. coli putA was determined, that of S. typhimurium putA was updated and the deduced PutA protein sequences were surveyed for catalytic domains and ligand binding sites. The two sequences were very similar (80.5% and 95% on the nucleic acid and protein levels, respectively). Residues 650 through 1130 of PutA were very similar to the sequences of P5C dehydrogenases and aldehyde dehydrogenases from both prokaryotes and eukaryotes. Glutamate 883 and cysteine 917 of PutA were conserved with the corresponding residues in P5C dehydrogenases and with those proposed to be active site residues in the aldehyde dehydrogenases. Those relationships suggest that gamma-glutamic semialdehyde, believed to equilibrate spontaneously with P5C, is the substrate for P5C dehydrogenases. Residues 340 through 590 of PutA were similar in sequence to proline dehydrogenases from Saccharomyces cerevisiae and Drosophila melanogaster. Limited similarities were also found between residues 315 through 357 of PutA and a consensus sequence near a putative active site and FAD-binding region shared by succinate dehydrogenase sequences from several organisms. Since residues 228 through 358 of PutA were similar in sequence to several serine-pyruvate aminotransferases, PutA is proposed to catalyze the hydrolysis of P5C (a Schiff's base intermediate) to gamma-glutamic semialdehyde. A carboxyl-terminal sequence that resembles a leucine zipper motif may be involved in association of PutA with put control region DNA.
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PMID:Sequence analysis identifies the proline dehydrogenase and delta 1-pyrroline-5-carboxylate dehydrogenase domains of the multifunctional Escherichia coli PutA protein. 796 12

Cyclosporin A is an immunosuppressive drug, which disrupts the activation of peripheral T-lymphocyte pool and blocks the maturation of thymocytes within the thymus. Normally, thymic nonlymphoid cells provide the optimal inductive microenvironment for development of T-lymphocytes. After application of cyclosporin A the complex alterations of the thymic microenvironment occur, affecting all types of nonlymphoid cells. All subsets of thymic epithelial cells are thoroughly changed. The subcapsular epithelial cells show the prominent enlargement of cytokeratin contents. In electron microscopy, however, these cells present the morpho-functional aspect of resting cells. The epithelial cells in deeper cortex become enlarged and stockier, whereby their cell processes appear more ramified and thicker. Thus, the cytoreticulum they create seems much denser. These cells strongly express MHC antigens. Their subcellular organization is suggestive of increased synthetic and secretory activity. The number of medullary epithelial cells is decreased. The cells with the most mature phenotype are the most prominently depleted and the ones with phenotypically and morphologically immature appearance predominate. The number of Hassall's bodies is also decreased. The number of cortical macrophages does not increase. However, these cells become enlarged showing the prominent changes in enzyme capacity, histochemical features and ultrastructural organization. Thus, they become similar to macrophages located in the cortico-medullary zone of the normal rat thymus. Cortical macrophages increase the activity of hydrolytic enzymes, acid phosphatase and nonspecific esterase, develop the strong activity of chloroacetate esterase, the strong activity of respiratory enzyme succinic dehydrogenase and begin to show the marked presence of prostaglandin synthase. Moreover, the cytoplasmic inclusions, which are aldehyde fuchsin- and PAS-positive and show sudanophilia, appear within cortical macrophages. In electron microscopy these cells show an abundant cytoplasm a very active appearance and the variety of vacuolar cytoplasmic inclusions. The mitoses of neighboring thymocytes are often seen. The number of interdigitating cells is decreased due to reduced size of thymic medulla, but these cells do not show the substantial phenotype changes. The description and classification of all types of nonlymphoid cells, which constitute the normal thymic microenvironment, is also presented. The functional significance and possible mechanisms of CSA-induced changes of the thymic microenvironment are discussed.
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PMID:Cyclosporin A-induced changes of the thymic microenvironment. A review of morphological studies. 981 May 10

THE ALDEHYDES INTRODUCED IN THIS PAPER AND THE MORE APPROPRIATE CONCENTRATIONS FOR THEIR GENERAL USE AS FIXATIVES ARE: 4 to 6.5 per cent glutaraldehyde, 4 per cent glyoxal, 12.5 per cent hydroxyadipaldehyde, 10 per cent crotonaldehyde, 5 per cent pyruvic aldehyde, 10 per cent acetaldehyde, and 5 per cent methacrolein. These were prepared as cacodylate- or phosphate-buffered solutions (0.1 to 0.2 M, pH 6.5 to 7.6) that, with the exception of glutaraldehyde, contained sucrose (0.22 to 0.55 M). After fixation of from 0.5 hour to 24 hours, the blocks were stored in cold (4 degrees C) buffer (0.1 M) plus sucrose (0.22 M). This material was used for enzyme histochemistry, for electron microscopy (both with and without a second fixation with 1 or 2 per cent osmium tetroxide) after Epon embedding, and for the combination of the two techniques. After fixation in aldehyde, membranous differentiations of the cell were not apparent and the nuclear structure differed from that commonly observed with osmium tetroxide. A postfixation in osmium tetroxide, even after long periods of storage, developed an image that-notable in the case of glutaraldehyde-was largely indistinguishable from that of tissues fixed under optimal conditions with osmium tetroxide alone. Aliesterase, acetylcholinesterase, alkaline phosphatase, acid phosphatase, 5-nucleotidase, adenosine triphosphatase, and DPNH and TPNH diaphorase activities were demonstrable histochemically after most of the fixatives. Cytochrome oxidase, succinic dehydrogenase, and glucose-6-phosphatase were retained after hydroxyaldipaldehyde and, to a lesser extent, after glyoxal fixation. The final product of the activity of several of the above-mentioned enzymes was localized in relation to the fine structure. For this purpose the double fixation procedure was used, selecting in each case the appropriate aldehyde.
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PMID:Cytochemistry and electron microscopy. The preservation of cellular ultrastructure and enzymatic activity by aldehyde fixation. 1397 66


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