Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.20 (alpha-glucosidase)
 4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The action of certain substances known to induce cellular alterations, or encounted in the oral cavity, on the accumulation of 18F by Streptococcus mutans GS-5 has been investigated. A 62-67% inhibition in the number of 18F atoms bound per mg dry weight of cells could be induced by a 15 min pretreatment with 2.7 X 10(-4) M cetyltrimethylammoniumbromide, 1 X 10(-1) M acetic anhydride, or 7 X 10(-2) M HCl. Plate counts indicated that alteration of the cellular composition rather than viability was responsible for this diminution in 18F accumulation. Prior exposure for 15 min of this organism to 1 M HCHO or 0.1 M NaOH did not alter 18F accumulation. Of the common salts encountered in the oral cavity, CaCl2 enhanced 18F binding. Pretreatment of the assay cells for 15-160 min with 0.1-10 mg/ml of trypsin, pronase, protease, alpha-glucosidase, dextranase, or lactoferrin had no significant effect on the accumulation of 18F. However, pre-exposure of cells for 60 min to 1-10 mg/ml of either amylase or lipase induced a 40-67% inhibition in the binding of 18F, while lysozyme enhanced the binding of 18F by the cells. It would appear then that the binding of 18F by S. mutans may be altered by certain substances encountered in the oral cavity.
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PMID:The action of selected agents on the accumulation of 18F by Streptococcus mutans. 618 42

The aglB and aglA genes from the starch/maltodextrin utilization gene cluster of Thermotoga neapolitana were subcloned into pQE vectors for expression in Escherichia coli. The recombinant proteins AglB and AglA were purified to homogeneity and characterized. Both enzymes are hyperthermostable, the highest activity was observed at 85 degrees C. AglB is an oligomer of identical 55-kDa subunits capable of aggregation. This protein hydrolyses cyclodextrins and linear maltodextrins to glucose and maltose by liberating glucose from the reducing end of the molecules, and it is a cyclodextrinase with alpha-glucosidase activity. The pseudo-tetrasaccharide acarbose, a potent alpha-amylase and alpha-glucosidase inhibitor, does not inhibit AglB but, on the contrary, acarbose is degraded quantitatively by AglB. Recombinant AglB is activated in the presence of CaCl2, KCl, and EDTA, as well as after heating of the enzyme. AglA is a dimer of two identical 54-kDa subunits, and it hydrolyses the alpha-glycoside bonds of disaccharides and short maltooligosaccharides, acting on the substrate from the non-reducing end of the chain. It is a cofactor-dependent alpha-glucosidase with a wide action range, hydrolysing both oligoglucosides and galactosides with alpha-link. Thereby, the enzyme is not specific with respect to the configuration at the C4 position of its substrate. For the enzyme to be active, the presence of NAD+, DTT, and Mn2+ is required. Enzymes AglB and AglA supplement one another in substrate specificity and ensure complete hydrolysis to glucose for the intermediate products of starch degradation.
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PMID:[Thermotoga neopolitina gene cluster, participating in degradation of starch and maltodextrins: expression of aglB and aglA gene in Escherichia coli, properties of recombinant enzymes]. 1459 17