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 properties of seven enzymes were studied in extracts from Myxobacter AL-1. The enzymes were isocitrate dehydrogenase (E.C.1.1.1.42), succinate dehydrogenase (E.C.1.3.99.1), alkaline phosphatase (E.C.3.1.3.1), alpha-glucosidase (E.C.3.2.1.20), beta-glucosidase (E.C.3.2.1.21), beta-galactosidase (E.C.3.2.1.23), and N-acetyl-glucosaminidase (E.C. 3.2.1.30). Four of these enzymes: isocitrate dehydrogenase, alpha-glucosidase, beta-glucosidase, and beta-galactosidase are cytosolic enzymes. Succinate dehydrogenase was found to be located on the cytoplasmic membrane system, whereas alkaline phosphatase and N-acetylglucosaminidase were considered as enzymes which bind the outer membranes resp. the cell wall. During the cell cycle, all enzymes have a pattern of discontinuous activity increase. Succinate dehydrogenase and isocitrate dehydrogenase exhibit a stepwise increase of activity, whereas the other enzymes follow the pattern of a peak enzyme.
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PMID:Studies on the cell cycle of Myxobacter AL-1. II. Activities of seven enzymes during the cell cycle. 2 Aug 61

Rat pancreatic endocrine tumours were induced by administration of streptozotocin plus nicotinamide. Fifteen to eighteen months later tumours with wet weights of 0.1 to 224 mg were isolated. These tumours were compared with normal rat pancreatic islets. Insulin release from perifused tumours was stimulated by D-glucose, L-leucine, 2-ketoisocaproate, and D-glyceraldehyde, potentiated by theophylline and inhibited by norepinephrine. Compared with isolated rat pancreatic islets, however, insulin secretory responsiveness to glucose stimulation and insulin content were reduced in tumour tissue. Hypoglycaemia in tumour bearing rats and impaired diffusion of insulin out of the tumours may explain this difference. The pattern of enzyme activities observed in tumour tissue was typical for pancreatic endocrine tissue. The activities of succinate dehydrogenase, the two types of the monoamine oxidase, and alpha-glucosidase were in the normal range in tumour tissue. Only the activities of 5'nucleotidase and glutamate dehydrogenase were decreased. Immunocytochemical analysis of the tumours revealed that they contained an average of 91% B-cells. In addition 8% of D-cells were encountered. Proportions of A-cells and PP-cells ranged below 1%. Thus this endocrine tumour of the pancreas with a high proportion of functionally intact B-cells is an interesting model for studying regulation of secretion and endocrine tumour development.
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PMID:Secretory, enzymatic, and morphological characterization of rat pancreatic endocrine tumours induced by streptozotocin and nicotinamide. 299 5

Analytical subcellular fractionation of tissue whole homogenates and microanalysis of organelle marker enzymes were used to study the activity and subcellular localization of enzymes implicated in HCO3 secretion in rat duodenal and gastric antral mucosae. The following organelles, characterized by their marker enzymes, were located in the density gradients: cytosol (lactate dehydrogenase), plasma membrane (5'-nucleotidase), peroxisomes (catalase), mitochondria (succinate dehydrogenase), endoplasmic reticulum (Tris-resistant alpha-glucosidase), lysosomes (N-beta-acetylglucosaminidase), and brush-border membrane (Zn2+-resistant alpha-glucosidase and alkaline phosphatase). Compared with gastric antrum, rat duodenal mucosa contained over twice the activity of HCO3-ATPase and of Na+-K+-ATPase but less than one-tenth the activity of carbonic anhydrase. Duodenal HCO3-ATPase activity was observed in both mitochondrial and brush-border membrane fractions, whereas antral HCO3-ATPase activity was confined to mitochondria. Na+-K+-ATPase activity was found largely in the basolateral membrane (duodenum) and plasma membrane (antrum). In both tissues carbonic anhydrase activity was localized to the cytosolic fraction. These observations offer further evidence that differing biochemical mechanisms underlie HCO3 secretion by gastric and duodenal epithelia.
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PMID:Activities and subcellular localizations of enzymes implicated in gastroduodenal bicarbonate secretion. 608 73

To define reproducible conditions for the homogenization of small-intestinal biopsy samples, tissue homogenization has been studied by the use of three different homogenizers. Tissue samples of increasing wet weights (0.5-10.8 mg) were homogenized in a fixed volume (1 ml) before DNA and protein were determined. The DNA to protein ratio was calculated for all wet weights and used as a measure for reproducible homogenization. The minimum tissue wet weight needed for analysis (2 mg) was determined from the values obtained for the DNA to protein ratio. Highly sensitive techniques are described in detail for the assay of brush border (maltase, lactase, sucrase, neutral alpha-glucosidase, alkaline phosphatase, gamma-glutamyl transferase, leucyl-beta-naphthylamidase), basolateral membrane (5'-nucleotidase), and mitochondrial (succinate dehydrogenase) marker enzymes and for four acid hydrolases (acid phosphatase, acid beta-D-galactosidase, N-acetyl-beta-D-glucosaminidase, acid diesterase) in human and rat jejunal mucosa. Linear kinetics have been established for all enzyme assays. The optimal dilution of tissue homogenate for the assay of the various enzymes has been determined to enable the determination of a maximum number of enzymes in each homogenate. The range of enzyme activities in samples of human and rat jejunal mucosa has been determined.
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PMID:Enzyme activities in human and rat jejunal mucosa. 667 54

A low-speed supernatant from dog liver was prepared and subjected to analytical subcellular fractionation using either preformed Percoll or reorientating sucrose density gradient centrifugation. In Percoll the following organelles, with marker enzymes and modal densities between brackets, were characterised: plasma membrane (alkaline phosphatase, 5' nucleotidase, gamma-glutamyl transferase, 1.039); endoplasmic reticulum (neutral alpha-glucosidase, 1.039); lysosomes (N-acetyl-beta-glucosaminidase, 1.087; alpha-mannosidase, 1.081) peroxisomes (catalase, 1.045) and mitochondria (succinate dehydrogenase, 1.081). In sucrose alkaline phosphatase had a bimodal particulate distribution (1.120, 1.187) distinct from that of 5' nucleotidase (1.160) and of gamma-glutamyl transferase (1.173). Other modal densities were: endoplasmic reticulum (1.187), lysosomes (1.227, 1.200), peroxisomes (1.213) and mitochondria (1.187). Further resolution was achieved by homogenisation in digitonin which disrupted lysosomes and, in sucrose, selectively increased the densities of the plasma membrane components. Both procedures therefore achieved distinct but quite different resolutions of organelles and should prove valuable for investigating subcellular pathology.
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PMID:Evaluation of preformed Percoll and reorientating sucrose density gradient centrifugation for the analytical subcellular fractionation of dog liver. 687 78