The Determination of Amylo-1,6-Glucosidase

Hers, Henri‐Géry; Verhue, Walter M.; Hoof, F. Van

doi:10.1111/j.1432-1033.1967.tb00133.x

Cited by 87 publications

(22 citation statements)

References 18 publications

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“…A ,! ?-amylase limit dextrin was prepared according to Hers et al [20] from shellfish glycogen (Sigma Chemical Company, St. Louis, Mo., U.S.A.). The Takamine enzyme solution was obtained by extracting 4 times 2 g of Takamine diazyme powder (Miles Laboratories, Elkhart, Ind., U.S.A.) with 20 ml of 0.1 M acetate buffer a t pH 4 ; this extract was kept a t 4" for up to I month and diluted 10-fold with water immediately before use.…”

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confidence: 99%

The Effect of Glucose and of a Treatment by Glucocorticoids on the Activation in vitro of Liver Glycogen Synthetase

et al. 1970

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The removal of glucose, AMP and other small molecules from mouse liver extract by filtration through Sephadex 6-25 has allowed us t o demonstrate that the activation in vitro of glycogen synthetase is much more rapidly attained in the presence of glucose and also when the animals have received prednholone 3 h before sacrifice. These effects are the result of a shortening of the lag period that precedes the activation of the synthetase; they are conveniently studied in filtrates that have been enriched with sulfate or phosphate ions. Like glucose, caffeine and nicotinamide shorten the lag period and are without action when this period is over; a-particulate glycogen has the opposite effect. No lag period is observed in the presence of AMP, particularly when associated with magnesium acetate. When a liver Sephadex filtrate is incubated in the absence of salts, glycogen synthetase b is converted into a partially active form that is rapidly transformed into synthetase a upon the addition of salt.These results support the hypothesis that glycogen synthetase phosphatase is initially present in the liver filtrate as a b enzyme, active only in the presence of AMP and magnesium; this b form is converted into its active, a, homologue through the action of a synthetase phosphatase activating enzyme, which is more active after a treatment with glucocorticoids, is stimulated by glucose, caffeine and nicotinamide and inhibited by glycogen, AMP and fluoride. I n the liver of an untreated animal, the enzyme i s predominantly in the b form [2,3]; it is activated within a few min after an intravenous load of glucose [4,6] or within 2 to 3 h after the administration of glucocorticoids [5-71. Once activated, the enzyme is rapidly reconverted into b after the injection of glucagon [5,8] epinephrine or cyclic AMP [5].The studies in Witro (9-111 support the hypothesis that the activation and the inactivation of the synthetase in liver occurs, as in muscle [12], by dephosphorylation and rephosphorylation, with a phosphatase and b a s e , respectively. The latter enzyme is stimulated by cyclic AMP and this effect adequately explains the inactivation of the synthetase under the action of glucagon or epinephrine. Up to now, it had not been possible to show unequivocally what part of the system was mod5ed by glucose and by glucocorticoids.Enzymes. Glycogen synthetase or UDPG: a-l,4-gluoan a-4-glucosyltransferase (EC 2.4.1.11) ; glycogen phosphorylaae or a-1,4-glucan: orthophosphate glucosyltransferese (EC 2.4.1.1) ; phosphorylase phosphatase or phosphorylase phosphohydrolaae (EC 3.1.3.17).

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confidence: 99%

The Effect of Glucose and of a Treatment by Glucocorticoids on the Activation in vitro of Liver Glycogen Synthetase

et al. 1970

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“…18) Preparation of phosphorylase limit dextrin from glycogen. Phosphorylase limit dextrin was prepared from glycogen essentially according to the method of Hers et al 20) A mixture of 200 mg glycogen and 60 units of phosphorylase a in 10 ml of 0.1 M sodium phosphate buffer, pH 7.4, was incubated in a cellophane bag and dialyzed against 0.1 M sodium phosphate buffer, pH 7.4. After 24 h, 20 units of phosphorylase a were added to the internal solution, and incubation and dialysis were continued for 24 h. The enzymatic reaction was stopped by heating at 100 C for 5 min, and the insoluble material produced was removed by centrifugation.…”

Section: Methodsmentioning

confidence: 99%

Purification of Glycogen Debranching Enzyme from Porcine Brain: Evidence for Glycogen Catabolism in the Brain

Makino

Omichi

2006

Bioscience, Biotechnology, and Biochemistry

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Amylo-1,6-glucosidase from porcine brain was purified to homogeneity by ammonium sulfate fractionation, followed by sequential steps of liquid chromatography on DEAE-Sephacel, Sephacryl S-300, and Super Q. The purified enzyme had both maltooligosaccharide transferase and amylo-1,6-glucosidase activities within a single polypeptide chain, and the combination of these two activities removed the branches of phosphorylase limit dextrin. Based on these results, the purified enzyme was identified as a glycogen debranching enzyme (GDE). The molecular weight of the brain GDE was 170,000 by gel-filtration and 165,000 by reducing SDS-PAGE. The pH profile of maltooligosaccharide transferase activity coincided with that of the amylo-1,6-glucosidase activity (pH optimum at 6.0). The existence of GDE as well as glycogen phosphorylase in the brain explains brain glycogenolysis fully and supports the hypothesis that glycogen is a significant source of energy in this organ.

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“…Phosphorylase-limited dextrin was prepared as described by Hers et al (29). Glycogen from E. coli (500 mg) was incubated with 37.5 g phosphorylase in 20 ml 0.1 M sodium phosphate buffer (pH 6.5) in dialysis tubing and dialyzed against the same buffer.…”

Section: Methodsmentioning

confidence: 99%

Reaction Kinetics of Substrate Transglycosylation Catalyzed by TreX of Sulfolobus solfataricus and Effects on Glycogen Breakdown

Nguyen

Park

Shim

et al. 2014

Journal of Bacteriology

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The Determination of Amylo-1,6-Glucosidase

Cited by 87 publications

References 18 publications

The Effect of Glucose and of a Treatment by Glucocorticoids on the Activation in vitro of Liver Glycogen Synthetase

The Effect of Glucose and of a Treatment by Glucocorticoids on the Activation in vitro of Liver Glycogen Synthetase

Purification of Glycogen Debranching Enzyme from Porcine Brain: Evidence for Glycogen Catabolism in the Brain

Reaction Kinetics of Substrate Transglycosylation Catalyzed by TreX of Sulfolobus solfataricus and Effects on Glycogen Breakdown

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