Propriétés catalytiques de l'α-glucosidase neutre du rein humain

Burlet, Georges De; Sudaka, P

doi:10.1016/s0300-9084(77)80080-1

Cited by 20 publications

(12 citation statements)

References 16 publications

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“…3), while higher concentrations led to a slight Substrate Inhibition. # m -values were determined by Michaelis-Menten, Lineweaver-Burk and Hanes plots; the mean value was 0.53 mmol/1, which is similar to values already reported for human urine (2) and human kidney (5). The activity of neutral α-glucosidase was inhibited competitively by turanose with respect to maitose s Substrate ( fig.…”

Section: Resultssupporting

confidence: 81%

“…Calculations based on the Lineweaver-Burk and Dixon plots revealed a mean Kr value of 5.9 mmol/1. The same type of Inhibition with a similar Aj-value was found for neutral α-glucosidase from human kidney (5). At higher ratios of maitose to turanose, no significant inhibitory effect on neutral ct-glucosidase activity was observed ( fig.…”

Section: Resultssupporting

confidence: 74%

“…Determinations were performed at optimal pHvalues for neutral α-glucosidase (around pH 7.0) s well s for acid α-glucosidase (around pH 4.0). But due to their broad pH-optima neutral α-glucosidase (EC 3.2.1.20, a-O-glucoside glucohydrolase) revealed considerable enzymatic activity under acidic Brought to you by | University of Arizona Authenticated Download Date | 6/6/15 12:00 AM conditions at pH 4.0 (5,6), whereas acid a-glucosidase (EC 3.2.1.3, 1,4-a-D-glucan glucohydrolase) revealed moderate activity at pH 7.0 (6,7,8). Thus by using optimal pH-values only it was impossible to differentiate between both enzymatic activities.…”

Section: Introductionmentioning

confidence: 99%

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Selective Determination of the Activities of Neutral and Acid α-Glucosidase Using Discontinuous Assays

Kochmann¹,

Kochmann²,

Pape³

et al. 1983

Clinical Chemistry and Laboratory Medicine

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Most biological fluids contain both neutral and acid α-glucosidase. Optimal conditions were therefore developed for the selective determination of the activity of neutral and acid ot-glucosidase, using 2-step, discontinuous assays. In the first Step of the assay of neutral α-glucosidase, glucose was liberated from maitose (citrate-phosphate buffer, pH 6.8, 20 mmol/1 maitose, 25 mmol/1 turanose). Under these incubation conditions, turanose inhibited the residual activity of acid α-glucosidase alnjost completely without influencing the activity of neutral α-glucosidase. In the first Step of the acid α-glucosidase'assay, glucose was liberated from maitose (citrate-phosphate buffer, pH 3.8, 50 mmol/1 maitose, 2 mol/1 potassium Chloride). Under these incubation conditions, potassium ions stimulate the activity of acid α-glucosidase and simultaneously inhibit almost completely the residual activity of neutral α-glucosidase. In the second step of the assay of neutral and acid α-glucosidase, the liberated glucose was measured by hexokinase/glucose-6-phosphate dehydrogenase. The effect of turanose and potassium ions on neutral and acid α-glucosidase from human urine was characterized. Selektive Bestimmung der Aktivit t von neutraler und saurer a-Glucosidase in diskontinuierlichen TestsZusammenfassung: Die meisten biologischen Fl ssigkeiten enthalten gleichzeitig Aktivit ten von neutraler und saurer a-Glucosidase. Es wurden optimale Bedingungen f r diskontinuierliche Tests in zwei Schritten zur selektiven Aktivit tsbestimmung von neutraler und saurer α-Glucosidase entwickelt. Im ersten Schritt der Bestimmung der neutralen α-Glucosidase wird Glucose aus Maltose freigesetzt (Citrat-Phosphat-Puffer, pH 6,8, 20 mmol/1 Maltose, 25 mmol/1 Turanose). Bei den gew hlten Inkubationsbedingungen hemmt Turanose die verbleibende Aktivit t von saurer α-Glucosidase fast vollst ndig, ohne die Aktivit t der neutralen aGlucosidase zu beeinflussen. Im ersten Schritt der Bestimmung der sauren α-Glucosidase wird Glucose aus Maltose freigesetzt (Citrat-PhosphatrPuffer, pH 3,8, 50 mmol/1 Maltose, 2 mol/1 Kaliumchlorid). Bei den gew hlten Inkubationsbedingungen stimulieren Kaliumionen die Aktivit t der sauren α-Glucosidase bei. gleichzeitiger fast vollst ndiger Hemmung der verbleibenden Aktivit t von neutraler α-Glucosidase. Im zweiten Schritt der Bestimmung der neutralen und sauren α-Glucosidase wird die freigesetzte Glucose mit der Hexokinasemethode gemessen. Der Effekt von Turanose und Kaliumionen auf die neutrale und saure aGlucosidase aus menschlichem Urin wurde charakterisiert.

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Section: Resultssupporting

confidence: 81%

Section: Resultssupporting

confidence: 74%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Selective Determination of the Activities of Neutral and Acid α-Glucosidase Using Discontinuous Assays

Kochmann¹,

Kochmann²,

Pape³

et al. 1983

Clinical Chemistry and Laboratory Medicine

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“…This may be explained by the high substrate concentrations used, which we have found to be inhibitory. Indeed substrate inhibition by maltosaccharides seems to be a general property of acid and neutral maltases (Palmer, 1971 a;Sivakami & Radhakrishnan, 1976;De Burlet & Sudaka, 1977;Giudicelli et al, 1980). It is noteworthy that all the substrates (with the exception of trehalose) undergo hydrolysis with similar maximal velocities.…”

Section: Discussionmentioning

confidence: 96%

“…Finally, the effects of a number of a-glucosidase inhibitors on the purified enzyme were studied (Table 3) (Palmer, 1971 b; Sivakami & Radhakrishnan, 1976;De Burlet & Sudaka, 1977;Giudicelli et al, 1980). This implies the existence of several binding subsites; the binding of maltotriose and starch will probably require a large site (adjusted to three to five glucose residues) including several zones involved in the binding of maltose and trehalose.…”

Section: Discussionmentioning

confidence: 99%

Purification and properties of neutral maltase from human granulocytes

Bayer

Vittori

Sudaka

et al. 1989

Biochemical Journal

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A procedure for the purification of neutral maltase from human polymorphonuclear leukocytes is described, involving solubilization with Triton X-100, proteolytic attack and three chromatographic steps: DEAE ion exchange, AcA 22 gel filtration and a second DEAE chromatography. The enzyme was obtained with a final specific activity of 30 units/mg of protein, comparable with that of other neutral maltases previously purified. The Mr of the enzyme was 550000 as determined by gel filtration. SDS/polyacrylamide-gel electrophoresis, under non-denaturing conditions, led to a major band of 500000 and a minor one of 260000, both active, suggesting a polymeric or aggregated form of the protein. The catalytic properties of the human granulocytic neutral maltase were investigated. The pH optimum was around 6. The enzyme exhibited a broad range of substrate specificity, hydrolysing di-and oligosaccharides with a(l -+ 2), a(l -+ 3) and z(1 -. 4) glucosidic linkages. The highest activities were observed for a(l -.4) glucose oligomers of three to five residues. It was also found to hydrolyse polysaccharides such as starch and glycogen. The results of the inhibition studies are interpreted in terms of the existence of a large site including several subsites. The enzyme properties are broadly similar to those observed for other purified neutral a-glucosidases, in particular that of human kidney origin. INTRODUCTIONNeutral maltases (a.-D-glucoside glucohydrolases, EC 3.2.1.20) are a-glucosidases which split glucose residues from the non-reducing ends of various a-glycans ranging

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Tris discriminates between the different α‐glucosidase activities from extracts of human neutrophils

Apodaca

Fernández

Fuente³

1990

J of Inher Metab Disea

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In an attempt to detect acid maltase deficiency in neutrophils from patients with type II glycogenosis, without interference from the 'renal' alpha-glucosidase activity present in these cells, we have evaluated the contribution of the renal component in the total activity measured at pH 4.0 in extracts of human neutrophils. The renal contribution is about 13-25% and renal glucosidase appears to be closely related to the enzyme present on the epithelium of small intestine, which is known to be inhibited by Tris. We have used this compound as a selective inhibitor of the renal component of alpha-glucosidase activity measured at pH 4.0 in total extracts of neutrophils. Our results demonstrate that 0.1 mol/L Tris is an inhibitor of the renal alpha-glucosidase present in neutrophils and can be used to reduce the interference from this enzyme in assays of acid maltase.

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Propriétés catalytiques de l'α-glucosidase neutre du rein humain

Cited by 20 publications

References 16 publications

Selective Determination of the Activities of Neutral and Acid α-Glucosidase Using Discontinuous Assays

Selective Determination of the Activities of Neutral and Acid α-Glucosidase Using Discontinuous Assays

Purification and properties of neutral maltase from human granulocytes

Tris discriminates between the different α‐glucosidase activities from extracts of human neutrophils

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