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)

It has previously been shown that mammalian RNA-peptidyl complexes are found in close association with tRNA, but can be separated from the bulk of the tRNA by benzoylated diethylaminoethylcellulose chromatography (Kull, F.J., and Soodak, M. (1971), Biochim. Biophys. Acta 246, l; Gadski, R.A., and Kull, F.J. (1973), Biochemistry 12, 1907). These studies also showed that under aminoacylation conditions the complex fractions were able to act as acceptors for certain amino acids and that the formation of porcine thyroid tyrosyl-complex II was particularly high. Because of this high acceptor function, and because of the importance of tyrosine to thyroid metabolism, further studies were conducted comparing some of the properties of porcine thyroid tyrosyl-complex II with those of porcine thyroid tyrosyl-tRNA. Porcine thyroid tyrosyl-tRNA synthetase was purified in excess of 200-fold and characterized. It was found that maximal aminoacylation was achieved at pH 8.1 in the presence of 150 mM KCl. The Km for tyrosine was determined to be 3.0 X 10(-6) M. The purified thyroid tyrosyl-tRNA synthetase was used under aminoacylation conditions to prepare radioactively labeled porcine thyroid tyrosyl-tRNA and tyrosyl-complex II. Comparisons made using reversed-phase column chromatography (RPC-5) showed distinct differences between the two aminoacylated species and revealed, in addition, a number of isoaccepting forms of tyrosine tRNA. Tyrosyl-complex II was also found to differ from tyrosyl-tRNA in that it is more stable to deacylation at pH 7.0 and at pH 4.4 and to degradation by ribonuclease A. In addition, tyrosyl-complex II, unlike tyrosyl-tRNA, is degraded by trypsin. Ribosomal binding studies showed that tyrosyl-complex II did not respond to the codons for tyrosine, UpApU and UpApC, whereas tyrosyl-tRNA responded to both. It is suggested that thyroid tyrosine complex II is representative of a group of related complexes that constitute the complex II fraction and that, although the complexes resemble tRNA in many respects, they have distinctly different characteristics than conventional tRNA.
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PMID:Thyroid Ribonucleic Acid-Iodopeptides. Comparison of Tyrosyl-Complex II and Tyrosyl-tRNA. 0 30

Pancreas of the cat was fractionated into its subcellular components by centrifugation through an exponential ficoll-sucrose density gradient in a zonal rotor. This enables a preparation of four fractions enriched in plasma membranes, endoplasmic reticulum, mitochondria and zymogen granules, respectively. The first fraction, enriched by 9- to 15-fold in the plasma membrane marker enzymes, hormone-stimulated adenylate cyclase, (Na+K+)-ATPase, and 5'-nucleotidase, is contaminated by membranes derived from endoplasmic reticulum but is virtually free from mitochondrial and zymogen-granule contamination. The second fraction from the zonal gradient shows only moderate enrichment of the above marker enzymes but contains a considerable quantity of plasma membrane marker enzymes and represents mostly rough endoplasmic reticulum. The third fraction contains the bulk of mitochondria and the fourth mainly zymogen granules as assessed by electron microscopy and marker enzymes for both mitochondria and zymogen granules, namely succinic dehydrogenase, trypsin and amylase. Further purification of the plasma membrane fractions by differential and sucrose step-gradient centrifugation yields plasma membranes enriched 40-fold in basal and hormone-stimulated adenylate cyclase and (Na+K+)-ATPase.
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PMID:Studies on isolated subcellular components of cat pancreas. I. Isolation and enzymatic characterization. 14 36

A character of rat liver mitochondria degradation after the heat treatment of animals is studied. It is found that mitochondria under the effect of elevated temperature do not considerably change their functional characteristics and thus they are capable to provide the normal rate of ATP synthesis, the rate of succinate oxidation being slightly increased. At the same time the heating caused the degradation of mitochondria which results in the decrease of their thermostability, in the increased susceptibility to lytic effect of trypsin and phospholipase D, and in the activation of succinate dehydrogenase and cytochrome c oxidase. The mitochondria degradation is due to the formation of "latent impairments" in the structure of mitochondria.
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PMID:[Some characteristics of mitochondrial multienzyme systems from rat liver mitochondria after heating of rats]. 20 Feb 83

The exposure of proteins at the surface of isolated chromatophores (i.e., the cytoplasmic face of intracytoplasmic membranes) of Rhodospirillum rubrum was studied by proteolysis as well as by enzymatic iodination with 125I. Analyses were performed after polyacrylamide gel electrophoresis of chromatophore proteins solubilized with sodium dodecyl sulfate. Reversible light induced proton uptake by partially digested chromatophores was used as a criterion for the integrity of the permeability barrier and thus, as evidence for proteolysis only of proteins outside of this barrier. Trypsin or alpha-chymotrypsin completely cleaved four proteins which were identified as the heavy subunit of succinate dehydrogenase (Mr = 64 000), the alpha- and beta-subunits of coupling factor ATPase (Mr = 55 000 and 51 000), and the heavy (H) subunit of photochemical reaction centers (Mr = 31 000). alpha-Chymotrypsin, in addition, attacked the protein (Mr = 9000) of light harvesting bacteriochlorophyll preparations. By enzymatic iodination, the same proteins were labeled as were digested with trypsin or alpha-chymotrypsin except for the protein of Mr = 9000. In addition, significant label was incorporated into three more proteins, one of which (Mr = 41 000) could be identified as a major protein of the cell wall. The complete cleavage with trypsin of four proteins exposed at the surface indicated that isolated chromatophores were homogeneously oriented regardless of the method employed for cell breakage, i.e., passage through a French pressure cell at different forces or osmotic shock of sphaeroplasts.
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PMID:Proteins exposed at the surface of chromatophores of Rhodospirillum rubrum: the orientation of isolated chromatophores. 41 10

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

Eight 2-(3,4-methylenedioxyphenyl)-5-arylamino1,3,4-oxadiazoles were synthesized, characterized by their sharp melting points, elemental analyses, and IR spectra, and evaluated for anticonvulsant activity. The protection afforded by oxadiazoles (100 mg/kg ip) against pentylenetetrazol (90 mg/kg sc)-induced convulsions ranged from 50 to 80%. All oxadiazoles inhibited the respiratory activity of rat brain homogenates during oxidation of pyruvate, alpha-ketoglutarate, and succinate. The presence of added nicotinamide adenine dinucleotide (NAD) to the reaction mixture during oxidation of pyruvate decreased the degree of inhibition. All oxadiazoles possessed antiproteolytic activity that was reflected by their ability to decrease trypsin-induced hydrolysis of bovine serum albumin. Such an inhibition was concentration dependent and ranged from 10.2 to 47.5 and from 15.7 to 71.8% by 0.5 and 1 mM oxadiazoles, respectively. All oxadiazoles competitively inhibited in vitro succinate dehydrogenase activity of rat brain homogenates.
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PMID:Anticonvulsant and antiproteolytic properties of 2,5-disubstituted oxadiazoles and their inhibition of respiration in rat brain homogenates. 66 May 24

The chlorophyll-protein complexes I and II have been isolated and anlyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis during greening and degreening of Chlamydomonas reinhardi y-1. At all stages of membrane formation, the complexes, when present, have a constant composition. Chlorophyll-protein complex I consists of a major polypeptide(s) of molecular weight 64,000 synthesized in the chloroplast, to which about 29 chlorophyll a molecules are bound. The complex is not detected when other polypeptides of chloroplastic origin, related to both Photosystem I and Photosystem II activities, are not synthesized. However, Photosystem I activity can develop in membranes in which chlorophyll-protein complex I is not detectable. Chlorophyll-protein complex II consists of two polypeptides of cytoplasmic origin, molecular weights 24,000 and 22,000, which bind 12 chlorophylls (a and b). The chlorophyll-protein complex II can be detected in membranes in which the development of photosystem II activity is prevented. Clipping of a Mr = 2000 fragment(s) from the Mr = 22,000 polypeptide following trypsin digestion of membranes, does not affect the complex. The detection of the complexes is possible only in membranes in which the simultaneous synthesis of both the chlorophyll and the corresponding polypeptides occurs. The 28,000 dalton polypeptide, reported to be present in the chlorophyll-protein complex II, comigrates with the complex but apparently is not part of the complex itself. The apparent molecular weight of the chlorophyll-protein complexes I and II are 88,000 and 28,000, respectively. The minimal true value for complex I is 89,000 or 154,000 and for complex II is 56,000.
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PMID:Appearance and composition of chlorophyll-protein complexes I and II during chloroplast membrane biogenesis in Chlamydomonas reinhardi y-1. 84 36

Significant increase of liver succinic dehydrogenase (SHD) activity was produced by carrageenin-induced edema in rats. Pretreatment with human placental extract "Placentrex" inhibited the increased liver SHD activity in a dose-dependent manner. "Placentrex" was found to have no effect on the liver SHD activity in normal rats. Furthermore, heat-induced erythrocyte lysis was inhibited to a substantial extent by "Placentrex" and was found to be almost dose-responsive. However, adenosine diphosphate (ADP)-induced platelet aggregation and trypsin activity were not changed in vitro by the "Placentrex". No alkaline phosphatase activity was found in this preparation. All these studies indicate that the membrane stabilization and depletion of adenosine triphosphate (ATP) synthesis may be the basis of anti-inflammatory effect of this drug.
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PMID:Anti-inflammatory effect of human placental extract: a biochemical mechanistic approach. 130 3

The arrangement of the large (70,000-Mr) and small (30,000-Mr) subunits of succinate dehydrogenase in the mitochondrial inner membrane was investigated by immunoblot analysis of bovine heart mitochondria (right-side-out, outer membrane disrupted) or submitochondrial particles (inside-out) that had been subjected to surface-specific proteolysis. Both subunits were resistant to proteinase treatment provided that the integrity of the inner membrane was preserved, suggesting that neither subunit is exposed at the cytoplasmic surface of the membrane. The bulk of the small subunit appears to protrude into the matrix compartment, since the 30,000-Mr polypeptide is degraded extensively during limited proteolysis of submitochondrial particles without the appearance of an immunologically reactive membrane-associated fragment: moreover, a soluble 27,000-Mr peptide derived from this subunit is observed transiently on incubation with trypsin. Similar data obtained from the large subunit suggest that this polypeptide interacts with the matrix side of the inner membrane via two distinct domains; these are detected as stable membrane-associated fragments of 32,000 Mr and 27,000 Mr after treatment of submitochondrial particles with papain or proteinase K, although the 27,000-Mr fragment can be degraded further to low-Mr peptides with trypsin or alpha-chymotrypsin. A stable 32,000-34,000-Mr fragment is generated by a variety of specific and non-specific proteinases, indicating that it may be embedded largely within the lipid bilayer, or is inaccessible to proteolytic attack owing to its proximity to the surface of the intact membrane, possibly interacting with the hydrophobic membrane anchoring polypeptides of the succinate: ubiquinone reductase complex.
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PMID:Topography of succinate dehydrogenase in the mitochondrial inner membrane. A study using limited proteolysis and immunoblotting. 199 68

It was shown on Wistar rats that trypsin and kallikrein decrease the activity of lactate dehydrogenase, alpha-glycerophosphate dehydrogenase, glycogen content and increase the activity of succinate dehydrogenase in neutrophils.
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PMID:[Effect of trypsin, kallikrein and kontrikal on the enzyme activity and cationic protein content of the blood neutrophils]. 242 65


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