A-o-Glucosidase

The leakage of immobilized p-o-fructofuranosidase, p-o-galactosidase, and glucoamylase from gels of poly(2-hydroxyethyl acrylate) or polydimethylacryl-amide has been studied.p-o-Fructofuranosidase and a-o-glucosidase immobilized within hollow fibres showed no detectable leakage and, when the fibres were pretreated with albumin, the stabilities of the immobilized enzymes approached those of the free enzymes. ... 

The results of a detailed comparison of the relative efficiencies of different procedures for solubilizing the membrane-bound a-o-glucosidases of porcine intestinal mucosa have been reported. Procedures for the selective solubilization of certain members of the complex group of a-D-glucosidases have b en developed. The selective solubilization led to the conclusion that separate a-D-glucosidases (isomaltase and limit dextrinase respectively) are involved in the hydrolysis of isomaltose and the a-limit dextrins formed from starch by a-amylase. 

An a-D-glucosidase purified from flint corn by precipitation with ammonium sulphate, ion-exchange chromatography, and gel-filtrations was homogeneous in ultracentrifugal and disc electrophoretic analysis. The enzyme (6.5 Sy mol. wt. 6.5 X 10 by gel filtration) showed a pH optimum of 3.6 for both maltose and soluble starch. The ratio of velocities of hydrolysis for maltose, phenyl a-D-glucopyranoside, and soluble starch was estimated to be 100 14.3 6.1. The a-o-glucosidase hydrolysed soluble starch by an exo action. 

The separation by polyacrylamide gel electrophoresis and subsequent analysis of the components of guinea-pig intestinal brush border membrane revealed the presence of inter alia enzyme complexes a-o-glucosidase-sucrose, a-o-glucohydrolase-glucoamylase, and a-o-glucosidase-sucrose a-o-glucohydro-lase. ... 

Fig. 3.—pH-Dependenceofthe Inhibition of -o-Glucosidase A, from Aspergillus wentiiby )3-D-Glucosylpyridinium Ion, left ordinate) and the Protonated Form of D-Glucosyl-amine right, calc, with pK, 5.6) and Nojirimycin (—A-, right, calc, with pK,... 

The principle of active-site-directed inactivation of glycosidases by gly-con-related epoxides can be extended to compounds having an exocyclic oxirane ring, either directly attached to the six-membered ring (32) or at some distance (33,34). Studies with -o-glucosidase from sweet almonds and intestinal sucrase-isomaltase revealed that, in spite of the higher intrinsic reactivity of these epoxides, this shift of the position of the epoxide function causes a 10- to 30-fold decrease of kj(max)/Ki, an effect which probably reflects the limited flexibility of the catalytic groups involved in the epoxide reaction. 

This enzyme [EC 3.2.1.41] (also known as a-dextrin endo-1,6-o -glucosidase, pullulan 6-glucanohydrolase,... 

G. Legler and L. M. O. Osama, Mechanism of action of glycosidase splitting enzymes. IV. Purification and properties of a P-glucosidase from Aspergillus oryzae, Hoppe Seyler s Zeitschr. Physiol. Chem., 349 (1968) 1488-1492. 

In 1987 2,6-dideoxy-2,6-imino-D-g(ycero-L-gM/o-heptitol (14), a chain-extended derivative of 1-deoxynojirimycin, was synthesized as a potential glucosidase inhibitor [50] and soon thereafter extracted from the leaves of the Panamesian plant Omphalea diandra L [51]. Coined a-homonojirimycin by the discoverers, this novel type of inhibitor exhibited pronounced activity against gluco-... 

It is regrettable that Australian chemists failed to discover another local alkaloid, namely castanospermine 3. It was left to an overseas group to collect and extract the seeds from a Queensland legume to yield this valuable alkaloid [6]. Castanospermine seems to display a broad biological activity which surpasses even that of swainsonine, being a particularly powerful competitive inhibitor of both a- and -o-glucosidases [7]. The alkaloid is plentiful enough in the... 

FlC. 1.—Relative Rates of Activity Against Glycosides at Various pH Values. [A. Hydrolysis of sucrose by /3-D-fructofuranosidase of Saccharomyces cerevisiae O, intact cells and A, toluene-treated cells (results of Wilkes and Palmer40). B. Maltose , fermentation by intact baker s yeast A, hydrolysis by a-D-glucosidase (results of Hestrin41 see also Ref. 42).]... 

Figure 3. Elution patterns of E-3 on a Bio-gel P-100 column. (%) CMC-saccharifying activity (5-min incubation) of eluates diluted 20-fold, (O) Avicel-saccharifying activity (30-min incubation), (A) p-glucosidase activity (15-min incubation), ( ) protein concentration measured in terms of the absorbance at 280 nm column 2.7 X 133 cm flow rate 5.0 mL/ hr one fraction 2.5 mL.

Trehalose is a nonreducing disaccharide (C12H22O11) isolated from the poisonous mushroom Amanita muscaria. Treatment with an a-glucosidase converts trehalose to two molecules of glucose, but no reaction occurs when trehalose is treated with a j3-glucosidase. When trehalose is methylated by dimethyl sulfate in mild base and then hydrolyzed, the only product is 2,3,4,6-tetra-O-methylglucose. Propose a complete structure and systematic name for trehalose. 

D-glucosidase of almond emulsin is without action on melezitose or turanose - Next there is the positive evidence that the enzyme a-D-glucosidase which is obtainable from yeast, malt, Aspergillus oryzae and some other organisms, hydrolyzes both turanose and melezitose, the latter to its three components. The action of enzymes thus discloses that both D-glucose units in melezitose are of the a-n-type, and melezitose becomes 3-[ a-o-glucopyrano3ylJ-D-fructofuranose < > a-n-glu-copyranose. 

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