Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.3.5.1 (succinate dehydrogenase)
8,177 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The enzymes from the venom of Heterometrus scaber, the indole compounds present and the toxic protein of the venom have been studied. The venom contains acid phosphatase, ribonuclease, 5'-nucleotidase, hyaluronidase, acetylcholine esterase and phospholipase. A. The indole compounds present in the venom have been identified as 5-hydroxytryptophan, tryptophan, serotonin and tryptamine, along with two unidentified indole compounds. The venom produces hyperglycaemia in sublethal doses and this has been found to be due to increased adrenaline secretion. The toxic protein of the venom has been obtained in a pure form by (NH4)2SO4 fractionation, followed by fractional precipitation with acetone and chromatography over DEAE-Sephadex. The toxic fraction has been found to be homogeneous on acrylamide gel electrophoresis. It is a glycoprotein (molecular weight 15 000) containing 1.74% glucosamine, 0.87% galactosamine, 0.313% sialic acid, 3.25% fucose and 0.45% of an unidentified neutral sugar. It did not show any enzyme activities, haemolytic activity or inhibition of succinate dehydrogenase activity but it produced hyperglycaemia in sublethal doses. The toxic level (intravenous administration in rats) was found to be 0.72 mg/kg body weight.
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PMID:Investigations on the venom of the South Indian scorpion Heterometrus scaber. 111 82

Transcription of the alpha 2-macroglobulin gene (alpha 2M) in rat hepatocytes is strongly induced during acute inflammations by interleukin 6 (IL6). An IL6-response region has previously been mapped in the promoter upstream sequence of this gene. The region consists of two adjacent elements (IL6-REs), the IL6-RE core (CTGGGAA, -164 to -158 bp) and the core homology (CTGGAAA, -184 to -178 bp), elements, that are located 20 bp apart. Both elements bind nuclear factors with very similar protein-DNA contact patterns when they are contained in their original sequence context. A protein-DNA complex III was obtained in gel mobility shift experiments using a probe individually representing the core site. With probes containing both the core and core homology sites, a hormone inducible complex II of slower mobility was obtained. Complex II consisted of multiple copies of the same protein or proteins with very similar molecular masses bound at both sites. The core homology site was the weaker binding site. With a probe containing two tandem copies of the core site, binding at the second site occurred with 81 times greater affinity when the first site was occupied, than when it was free. Thus, the factor binding at the IL6-REs, the IL6-RE binding protein (IL6 RE-BP), was capable of co-operatively interacting with itself. Another factor, IL6-DBP/LAP, has recently been shown to be involved in the regulation of a major subgroup of acute phase genes by IL6. Using recombinant IL6-DBP/LAP and corresponding antisera, we demonstrated here that the IL6 RE-BP of the alpha 2M gene was distinct from IL6-DBP/LAP and from the related factor DBP. Thus, two major IL6-response elements can be distinguished: type 1 elements occurring in the human C-reactive protein, hemopexin and haptoglobin genes and utilizing IL6-DBP/LAP; and type 2 elements occurring in the rat alpha 2M, and alpha 1-acid glycoprotein genes, and utilizing a different IL6 RE-BP. The IL6 RE-BP of the alpha 2M gene was also shown to be distinct from the transcription factor NF kappa B. The IL6RE-BP had relative molecular mass of Mr = 46,000, distinct from IL6-DBP/LAP (Mr = 32,000) and NF kappa B (Mr = 50,000) and its overall DNA binding capacity was induced under acute phase conditions.
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PMID:Interleukin 6 response factor binds co-operatively at two adjacent sites in the promoter upstream region of the rat alpha 2-macroglobulin gene. 172 49

Two-dimensional gel electrophoresis (2-D) was used to resolve the plasma membrane proteins from cultured human retinal pigment epithelial cells. The cells were metabolically labeled either with [35S]methionine to reveal proteins in general or with [3H]glucosamine or [3H]fucose which are more specific for glycoprotein visualization. The cell surface proteins were also iodinated, using the lactoperoxidase--glucose oxidase technique. These labeled membranes were separate into plasma membrane-enriched fractions by subjecting the water-shocked postnuclear supernatant to a discontinuous sucrose-density gradient. The five resulting membrane fractions were assayed for protein, RNA (microsomes), galactosyltransferase (Golgi membranes), 5'-nucleotidase (plasma membranes), and succinate dehydrogenase (mitochondrial membranes) and were examined by electron microscopy. The plasma membranes were enriched with minimal contamination at the 0.6-0.85 M (F2) and 0.85-1.0 M (F3) sucrose interfaces based on these biochemical and morphological criteria. Examination of 2-D autoradiographic profiles of F2 and F3 showed that approximately 180 proteins or protein subunits had incorporated [35S]methionine. Certain proteins were also labeled by [3H]glucosamine and [3H]fucose, and surface-labeled by iodination. This was especially true of 17 different high-molecular-weight (43-139 X 10(3) MW) very acidic glycoproteins which formed a constellation of spots. These glycoproteins, as well as others, were also seen in the whole-cell acidic glucosamine-labeled 2-D profiles, where about 150 proteins were detected. A total of 39 proteins were catalogued, of which 34 were detectable in the plasma membrane-enriched fractions. The results show that the use of subcellular fractionation, specific precursors, and labeling techniques aids in the detection and characterization of minor proteins in 2-D gels.
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PMID:Isolation and characterization of plasma membrane proteins of cultured human retinal pigment epithelium. 243 67

The purpose of this study was to develop a primary cell culture system of rat gastric fundic epithelial cells. The cells, isolated enzymatically, were cultured in Coon's modified Ham's F-12 medium supplemented with 10% fetal bovine serum, 15 mM HEPES buffer, fibronectin, and antibiotics. The inoculated cells started to grow rapidly on day 1 (doubling time, 26 h). The cells reached confluency on day 3. On phase contrast microscopy, over 90% of cells possessed epithelial characteristics. Histochemical studies showed (a) 90% of the epithelial cells contained PAS positive granules, (b) 5% of the cells gave a strong reaction for succinic dehydrogenase activity (presumably parietal cells), and (c) immunohistochemical localization of pepsinogen was negative. Ultrastructurally, microvilluslike structures, junctional complexes, Golgi apparatus, mitochondria, rough-surfaced endoplasmic reticulum, and mucous granules were observed. Mitotic figures were clearly observed on Giemsa staining and the mitotic index was maximum on day 2. Autoradiographic and biochemical studies showed these cells possessed the capability to synthesize deoxyribonucleic acid and this ability was maximum on day 2. These cells were able to synthesize and to secrete glycoprotein and this function was significantly increased by 16,16-dimethyl prostaglandin E2. Cyclic adenosine monophosphate produced by the cultured cells was enhanced by addition of 16,16-dimethyl prostaglandin E2 (p less than 0.01). This in vitro system provides a valuable model for studies of cellular functions of gastric mucosa.
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PMID:Cell culture of rat gastric fundic mucosa. 629 Mar 9

The three main segments of the elephant epididymis were examined for the occurrence, in the spermatozoa and lining epithelium, of carbohydrates, neutral lipids and phospholipids, ATPase, alkaline phosphatase, succinic dehydrogenase, glucose-6-phosphate dehydrogenase, diaphorases, hydroxysteroid dehydrogenases, acid phosphatase and non-specific esterase. The most distinct feature of the carbohydrate content of the epididymis was a layer of acidic, alcian blue-positive glycoprotein over the luminal surface of the epithelium, particularly in the terminal segment. PAS-positive, diastase-resistant inclusions were also found throughout the epdidymis. Neutral lipid occurred as droplets above and below the nucleus in the epithelium of the middle segment, and as supranuclear accumulations in the terminal segment. All the enzymes except the steroid dehydrogenases were detected in the epididymal epithelium, and all except the steroid dehydrogenases and acid phosphatase were detected in the spermatozoa. There was considerable variation in the intensity of the cytochemical reactions in the epithelium, but not in the spermatozoa, in different regions of the epididymis. In general, the enzymes involved in active transport showed strongest reactions in the initial and terminal segments, the reactions in the stereocilia being the most intense. The enzymes involved in energy metabolism showed strongest reactions in the middle and terminal segments, with the activity being fairly evenly distributed throughout the cytoplasm of the principal cells. However, the two lysosomal enzymes which were studied showed quite different distributions: the reactions for acid phosphatase were strongest in the initial and middle segments, whilst the reactions for non-specific esterase were strongest in the middle and terminal segments. It is suggested that the initial segment is involved in absorptive and anabolic activity, the middle segment in anabolic activity, and the terminal segment (where spermatozoa are stored ready for ejaculation) in considerable metabolic activity and active transport of substrates across the epithelium.
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PMID:Studies of the deferent ducts from the testis of the African elephant, Loxodonta africana. II. Histochemistry of the epididymis. 644 36

Anterograde or retrograde perfusion of rat liver with digitonin selectively permeabilizes the periportal or the perivenous zone of the hepatic lobule. Digitonin perfusion is used to analyze the effluents released by permeabilized hepatocytes or, combined with collagenase perfusion, to obtain cell suspensions enriched in either periportal or perivenous hepatocytes. Despite the wide use of digitonin to study lobular heterogeneity, its affects on rat hepatocytes are not well documented. We therefore analyzed the effects of digitonin perfusion on the intracellular content of rat hepatocytes by combining electron microscopy, histoenzymology, immunohistochemistry, and in situ hybridization. At the concentration currently used for the study of lobular heterogeneity, digitonin perfusion induced a marked cytosolic clarification of permeabilized hepatocytes, while most organelles except mitochondria were well preserved. In the digitonin-altered zones, there was no histochemical detection of non-membrane-bound enzymes (lactate dehydrogenase, glutamate dehydrogenase), whereas membrane-bound enzymes (succinate dehydrogenase, beta-hydroxybutyrate dehydrogenase, NADPH dehydrogenase, glucose-6-phosphatase) were still detected. Immunohistochemistry and in situ hybridization revealed significant amounts of several plasma proteins (albumin, alpha 2-macroglobulin, alpha 1-inhibitor 3, alpha 1-acid glycoprotein) and their respective mRNAs in digitonin-permeabilized hepatocytes. The demonstration that digitonin-permeabilized hepatocytes retain many intracellular constituents shows that biochemical analysis of cellular effluents released from digitonin-permeabilized hepatocytes must be interpreted with caution and that the apparent characteristics of cell suspensions obtained by the digitonin-collagenase technique might be significantly altered by contamination with permeabilized hepatocytes from the opposite zone.
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PMID:Effects of digitonin on the intracellular content of rat hepatocytes: implications for its use in the study of intralobular heterogeneity. 815 38

Thyroid-associated ophthalmopathy (TAO) is a progressive orbital disorder associated with Graves' hyperthyroidism and, less often, Hashimoto's thyroiditis in which autoantibodies react with orbital antigens and lead to exophthalmos and eye muscle inflammation. Eye muscle (EM) membrane proteins initially reported as 55 and 64 kd are the best markers of ophthalmopathy. The "64-kd protein" is now shown to be the flavoprotein subunit of mitochondrial succinate dehydrogenase and to have a correct molecular weight of 67 kd. We have cloned a fragment of a novel eye muscle protein, which we call G2s, and sequenced 1.4 kb of the full length cDNA. G2s does not share any significant homologies with other reported proteins. The 5.9 kb G2s mRNA, that corresponds to a protein of approximately 220 kd, is expressed in EM, other skeletal muscle and thyroid, but not in other tissues tested. We have also cloned and sequenced a 63-kd eye muscle protein identified as the calcium binding protein calsequestrin. Antibodies against calsequestrin were found in 40% of patients with active ophthalmopathy, but in 0% of normal subjects. Finally, we have sequenced a 19 amino acid fragment of a 55-kd porcine eye muscle membrane protein that exactly matched porcine and human sarcalumenin, a 160-kd glycoprotein localized in the lumen of the longitudinal sarcoplasmic reticulum of the skeletal muscle fiber where it binds calcium. A 53-kd glycoprotein fragment of the molecule corresponds to the 55-kd protein. In a preliminary study, serum antibodies against purified sarcalumenin were detected in 40% of patients with active TAO of less than 1 year duration, but in no controls tested. We porpose that the primary autoantigen in TAO is G2s, which would also explain the association of ophthalmopathy with thyroid autoimmunity, and that antibodies against the intracellular proteins flavoprotein, calsequestrin, and sarcalumenin are secondary markers of an immune-mediated reaction in eye muscle in patients with thyroid autoimmunity.
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PMID:Role of the eye muscles in thyroid eye disease: identification of the principal autoantigens. 966 97

Vesicular stomatitis virus glycoprotein (VSV-G) is a transmembrane protein that functions as the surface coat of enveloped viral particles. We report the surprising result that VSV-G uses the tyrosine-based di-acidic motif (-YTDIE-) found in its cytoplasmic tail to recruit adaptor protein complex 3 for export from the trans-Golgi network. The same sorting code is used to recruit coat complex II to direct efficient transport from the endoplasmic reticulum to the Golgi apparatus. These results demonstrate that a single sorting sequence can interact with sequential coat machineries to direct transport through the secretory pathway. We propose that use of this compact sorting domain reflects a need for both efficient endoplasmic reticulum export and concentration of VSV-G into specialized post-trans-Golgi network secretory-lysosome type transport containers to facilitate formation of viral coats at the cell surface.
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PMID:The delta subunit of AP-3 is required for efficient transport of VSV-G from the trans-Golgi network to the cell surface. 1199 54

Glycoproteins exit the endoplasmic reticulum (ER) of the yeast Saccharomyces cerevisiae in coat protein complex II (COPII) coated vesicles. The coat consists of the essential proteins Sec23p, Sec24p, Sec13p, Sec31p, Sar1p and Sec16p. Sec24p and its two nonessential homologues Sfb2p and Sfb3p have been suggested to serve in cargo selection. Using temperature-sensitive sec24-1 mutants, we showed previously that a secretory glycoprotein, Hsp150, does not require functional Sec24p for ER exit. Deletion of SFB2, SFB3 or both from wild type or the deletion of SFB2 from sec24-1 cells did not affect Hsp150 transport. SFB3 deletion has been reported to be lethal in sec24-1. However, here we constructed a sec24-1 Deltasfb3 and a sec24-1 Deltasfb2 Deltasfb3 strain and show that Hsp150 was secreted slowly in both. Turning off the SEC24 gene did not inhibit Hsp150 secretion either, and the lack of SEC24 expression in a Deltasfb2 Deltasfb3 deletant still allowed some secretion. The sec24-1 Deltasfb2 Deltasfb3 mutant grew slower than sec24-1. The cells were irregularly shaped, budded from random sites and contained proliferated ER at permissive temperature. At restrictive temperature, the ER formed carmellae-like proliferations. Our data indicate that ER exit may occur in vesicles lacking a full complement of Sec23p/24p and Sec13p/31p, demonstrating diversity in the composition of the COPII coat.
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PMID:Endoplasmic reticulum exit of a secretory glycoprotein in the absence of sec24p family proteins in yeast. 1594 8

The absence of dystrophin and resultant disruption of the dystrophin glycoprotein complex renders skeletal muscles of dystrophic patients and dystrophic mdx mice susceptible to contraction-induced injury. Strategies to reduce contraction-induced injury are of critical importance, because this mode of damage contributes to the etiology of myofiber breakdown in the dystrophic pathology. Transgenic overexpression of insulin-like growth factor-I (IGF-I) causes myofiber hypertrophy, increases force production, and can improve the dystrophic pathology in mdx mice. In contrast, the predominant effect of continuous exogenous administration of IGF-I to mdx mice at a low dose (1.0-1.5 mg.kg(-1).day(-1)) is a shift in muscle phenotype from fast glycolytic toward a more oxidative, fatigue-resistant, slow muscle without alterations in myofiber cross-sectional area, muscle mass, or maximum force-producing capacity. We found that exogenous administration of IGF-I to mdx mice increased myofiber succinate dehydrogenase activity, shifted the overall myosin heavy chain isoform composition toward a slower phenotype, and, most importantly, reduced contraction-induced damage in tibialis anterior muscles. The deficit in force-producing capacity after two damaging lengthening contractions was reduced significantly in tibialis anterior muscles of IGF-I-treated (53 +/- 4%) compared with untreated mdx mice (70 +/- 5%, P < 0.05). The results provide further evidence that IGF-I administration can enhance the functional properties of dystrophic skeletal muscle and, compared with results in transgenic mice or virus-mediated overexpression, highlight the disparities in different models of endocrine factor delivery.
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PMID:Systemic administration of IGF-I enhances oxidative status and reduces contraction-induced injury in skeletal muscles of mdx dystrophic mice. 1662 99


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