Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.4.1.18 (branching enzyme)
 628 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. A morphological mutant of Neurospora crassa, smco 9, (R2508) that exhibits colonial morphology when grown on sucrose or on maltose, showed a partial reversal of this morphology toward that of the wild type when it was grown on potato starch or on isomaltose. 2. A common feature of both potato starch and isomaltose is the presence of alpha-1, 6 glucosidic linkages. This suggested that these morphological effects might be due to differences in alpha-1,4 glucan: alpha-1,4 glucan 6 glycosyltransferase, (EC 2.4.1.18) commonly known as "the branching enzyme". 3. The branching enzyme was purified from wild type, Neurospora crassa, and from the semicolonial mutant, R2508, both grown on sucrose or on potato starch. It has a molecular weight of 140,000 as estimated by gel filtration on a Bio Gel A 1.5 m column. This enzyme plus phosphorylase a in an unprimed reaction catalyzes the synthesis of a branched polysaccharide in vitro. 4. No branching enzyme activity was apparent in extracts of the mutant R2508, grown on potato starch until a thermolabile inhibitor was removed by fractionation on a DEAE column. 5. This inhibitor has a molecular weight greater than 100,000 as estimated on a P-100 polyacrylamide gel column. The specificity of the inhibitor is not absolute in that it inhibits glycogen synthetase in addition to the branching enzyme in Neurospora.
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PMID:Differential inhibition of branching enzyme in a morphological mutant and in wild type Neurospora. Influence of carbon source in the growth medium. 12 59

Implantation of cobalt powder in the cerebral cortex of rat determines an epileptogenic focus where two types of reactive astrocytes are observed. The first type is mostly represented in the subcortical white matter but it does exist in the cortex around the implant. Phosphorylase and branching enzyme are both very active in these cells which are filled with glycogen. The second type is limited to the cortex and phosphorylase activity leads to an unbranched polysaccharid. These cells correspond to the "activated astrocytes" described by the authors in a previous paper and observed round irritative lesions which, in the cerebral cortex, produce epileptogenic foci.
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PMID:[Phosphorylase and glucosyltransferases at the level of reactive astrocytes. A histochemical study]. 15 Sep 29

During the investigation of the histochemical synthesis of glycogen particles from glucose 1-phosphate by the phosphorylase-branching glycosyltransferase system in various tissue cells, it was observed that focal synthesis localized in a certain area of the cytoplasm occurred in some cells. This differed from the usual synthesis in which particles of similar size were synthesized within the cytoplasm. Otherwise, cytoplasmic particles of various size were also synthesized in other cells under the same histochemical condition. The possible significance of the presence of these patterns in glycogen synthesis is discussed.
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PMID:Intracellular localization and size of glycogen particles in glycogen synthesized under histochemical conditions. 17 57

The aim of the present work was to study by means of histochemical and chemical methods the 7-day course of changes in carbohydrate metabolism in the liver of male rats induced by a single dose of isoprenaline of 50 mg/kg administered subcutaneously. A statistically significant reduction was seen both in the level of free glycogen and lactate within 24 hours. The decrease of pyruvate level was not so marked. At the same time, there was increased, and within the hepatic lobules also extended activity of enzymes catalyzing glycogenolysis, i.e. alpha-glucan phosphorylase and particularly the branching Q-enzyme, glucose-6-phosphatase and LDH, whereas the level of malate and activity of SDH, which are constituents of the Krebs cycle, were found to be reduced. Cytochrome oxidase activity was changed after 24 hr compared to the controls. The obtained results indicate that an extensive glycogenolysis occurs in the liver of rats in the 24 hr following s.c. administration of isoprenaline, the major part of liver glycogen being degraded through glucose-6-phosphate to blood glucose and its metabolism via the Krebs cycle reduced. The observed metabolic changes are of reversible character and tend to normalize over the 2nd and 3rd day following isoprenaline administration.
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PMID:Study of histochemical and biochemical changes in the liver of rats induced by high doses of isoprenaline. 20 78

4 choroidal melanomas have been studied by electron histochemical techniques for phosphorylase activity. Of the 4 melanomas studied, 2 were spindle B and 2 were epitheloid cell types. Electron micrographs of the tumour cells incubated in the medium revealed that polyglucose particles synthesized by phosphorylase and branching glycosyltransferase were found in both spindle B and epitheloid cells. Synthesized polyglucose particles in both spindle B and epitheloid cells showed 2 patterns. The one was fine granular form and the other was the deposition of amorphous particles which greatly expanded the cytoplasmic matrices. Melanophages in both cell types also showed 2 patterns of synthesized polyglucose particles, fine granular and amorphous. It is concluded that both phosphorylase and branching glycosyltransferase are active in both spindle B and epithelioid cells of choroidal melanomas and their melanophages. It is also indicated that there is no difference in glycolysis among these cells of melanomas.
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PMID:Electron histochemical study of phosphorylase system in choroidal melanoma. 40 30

The stratified squamous epithelium in eleven cervical cone biopsies was studied for localization of glycogen, glycogen synthetase, branching enzyme and amylophosphorylase in areas showing normal, dysplastic epithelium and carcinoma in situ. In the normal cervix glycogen was found to be present in the intermediate and superficial cells, amylophosphorylase activity was present in the basal and parabasal layers and the branching enzyme was found largely in the lower and middle zone of the intermediate layer. As the degree of abnormality increased, a progressive decrease of glycogen and branching enzyme and increasing amylophosphorylase was found, suggesting that amylophosphorylase could be a constitutive enzyme in normal, dysplastic and neoplastic cells. The method for localization of glycogen synthetase activity was not sufficiently reproducible nor sensitive for conclusions to be drawn.
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PMID:Histochemical studies of glycogen metabolizing enzymes in normal and abnormal human cervical epithelium. 81 Oct 55

Electron histochemical techniques for glycogen synthetase has been applied to the living retina of the chick and the polyglucose particles synthesized from UDPG in the paraboloid of the accessory cone were compared with those synthesized by the conventional histochemical techniques. In the retina incubated in the medium for glycogen synthetase in vivo, synthesized polyglucose particles were located in the cytoplasmic matrices and most of the particles were less than 200 A in diameter. These particles were rather well stainable with lead citrate and filled the cytoplasmic matrices. However, the tubular structures were not flattened, but slightly dilated. Compared with polyglucose particles synthesized in vitro by glycogen synthetase, those demonstrated by the in vivo histochemical techniques showed closer resemblance to native glycogen particles in size and stainability with lead citrate. The polyglucose particles synthesized from UDPG by glycogen synthetase were apparently different from those synthesized from glucose-1-phosphate by phosphorylase and branching glycosyltransferase.
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PMID:Polyglucose particles histochemically synthesized by glycogen synthetase activity in the living chick retina. 82 86

Ultrastructural and histochemical studies on human gastric cancer cells disclosed the presence of native and synthesized glycogen particles. The glycogen particles were investigated in the histochemical synthesis of glycogen particles from glucose 1-phosphate by the phosphorylase-branching glycosyltransferase system and non-incubated native glycogen in human gastric adenocarcinoma tubulare. It was observed that focal synthesis localized inthe intracytoplasmic matrix and intranucleus. Intranuclear synthesized glycogen appeared as a rosette form ranging from 1100 to 1300 A in diameter and free particles ranging from 325 to 900 A in diagmeter. The synthesis of glycogen appeared in the nucleus as well as in the cytoplasm of the human gastric cancer cells, and the synthesized glycogen was observed as a group of particles. Newly formed glycogen particles appeared occasionally in the interchromatin area as a large macromolecular structure of rosette form. Native glycogen appeared as a free-particle (250-333 A, medium =300 A) and aggregated rosette from (694-1050 A, medium=917 A) in the autophagosome of gastric cancer cells. There was not, however, a native glycogen particle in the nuclei of gastric cancer cells. Under certain conditons the nuclei of gastric cancer cells can acquire the capacity to synthesize glycogen.
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PMID:Intranuclear synthesized and native glycogen particles in human gastric cancer: ultrastructure and histochemistry. 83 12

The body posterior to the ovary of Schistosoma haematobium females was investigated. Glycogen, glycogen phosphorylase a (EC 2.4.1.1) and glycogen branching enzyme (EC 2.4.1.18) activities were detected in the subtegumental muscle system, parenchyma and mature vitelline cells, whereas no activities were detected in the tegument and immature vitelline cells of the parasite. Administration of a single niridazole dose of 250 mg kg-1 to the pouched mouse (Saccostomus camestris) produced the following changes in S. haematobium females: a relatively rapid depletion of glycogen stores due to disruption of the absorptive surface of the parasite, and to an increase in the activity of glycogen phosphorylase a; a reduction in the phosphorylase a to phosphorylase b-conversion capacity of glycogen phosphorylase phosphatase (EC 3.1.3.17); a decrease in glycogen branching enzyme activity; and a relatively rapid degeneration of parasite cells possibly due to their loss of endogenous energy reserves.
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PMID:Schistosoma haematobium: histochemistry of glycogen, glycogen phosphorylase a and glycogen branching enzyme in niridazole-treated females. 156 21

A Butyrivibrio fibrisolvens H17c glgB gene, was isolated by direct selection for colonies that produced clearing on starch azure plates. The gene was expressed in Escherichia coli from its own promoter. The glgB gene consisted of an open reading frame of 1,920 bp encoding a protein of 639 amino acids (calculated Mr, 73,875) with 46 to 50% sequence homology with other branching enzymes. A limited region of 12 amino acids showed sequence similarity to amylases and glucanotransferases. The B. fibrisolvens branching enzyme was not able to hydrolyze starch but stimulated phosphorylase alpha-mediated incorporation of glucose into alpha-1,4-glucan polymer 13.4-fold. The branching enzyme was purified to homogeneity by a simple two-step procedure; N-terminal sequence and amino acid composition determinations confirmed the deduced translational start and amino acid sequence of the open reading frame. The enzymatic properties of the purified enzyme were investigated. The enzyme transferred chains of 5 to 10 (optimum, 7) glucose units, using amylose and amylopetin as substrates, to produce a highly branched polymer.
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PMID:Characterization of the Butyrivibrio fibrisolvens glgB gene, which encodes a glycogen-branching enzyme with starch-clearing activity. 193 80


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