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

A method for the high-performance liquid chromatographic assay of the relative activities of serum pancreatic and salivary alpha-amylase has been developed, using maltopentaose reductively aminated with 2-aminopyridine as a fluorescent substrate. Both enzymes showed similar modes of action, cleaving the second and the third (from the non-reducing terminal) interglycosidic linkages of this substrate. However, the relative ease of cleavage of these two sites by the pancreatic enzyme was significantly different from that by the salivary enzyme. Therefore, determination of the molar ratio of the cleavage products by HPLC could lead to estimation of the activity ratio of these enzymes. The optimum chromatographic conditions for HPLC were as follows: column, LiChrosorb RP-18 (Merck, 7 microns, 250 X 4 mm I.D.); column temperature, ambient; eluent, 0.01% orthophosphoric acid-acetonitrile (4:1, v/v) containing 2.4 mM sodium laurylsulphate; flow-rate, 1.0 ml/min; wavelengths for fluorimetric detection, 320 nm (excitation)/400 nm (emission). The problem of interference by serum alpha-glucosidase was solved by specific inhibition with tris (hydroxymethyl) aminomethane and erythritol. The data obtained by the proposed method correlated well with those produced by the conventional method based on electrophoresis.
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PMID:Liquid chromatographic assay of the relative activities of serum pancreatic and salivary alpha-amylase using reductively pyridylaminated maltopentaose as a fluorescent substrate. 349 44

An enzymatic assay for the determination of alpha-amylase in serum was developed which employed a soluble substrate, maltoheptaose, and a coupled enzymatic indicator reaction consisting of alpha-glucosidase and the hexokinase-glucose-6-phosphate dehydrogenase system. We used high-performance liquid chromatography (HPLC) to establish the action pattern of maltoheptaose under the test conditions: (A) the action pattern of alpha-amylase, (B) that of the combined action of alpha-amylase and alpha-glucosidase. Conductive to this effect was: the availability of pure maltoheptaose and human pancreatic alpha-amylase; the development of an adequate procedure for sample pretreatment (partition chromatography on a mixed-bed ion exchange) and of an HPLC system for separation of substrate and reaction products without interference from by products of the assay (partition chromatography on a cation-exchange column with acetonitrile-water); and the use of a new, very sensitive refractometric detector revealing sugar amounts as low as 40 ng. We derived the following stoichiometric equations: (see formula index).
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PMID:Action pattern of human pancreatic alpha-amylase on maltoheptaose, a substrate for determining alpha-amylase in serum. 616 29

Formulations of traditional medicines are usually made up of complex mixture of herbs. However, effective quality control methods in order to select right quality materials are lacking. Though Piper longum is a widely used herb in several Ayurvedic formulations prescribed for various diseases, there is no analytical method in the literature so far which can help in selecting the right quality material with proper proportions of the active ingredients (alpha-glucosidase-I enzyme inhibitory principles). We employed a systematic bioassay guided fractionation method and isolated pipataline, pellitorine, sesamin, brachystamide B and guineensine as active principles. A reversed-phase high-performance liquid chromatography method was developed to quantify these active principles in the plant material, which can serve as an effective quality control tool. The separation was carried out using a Discovery HS F5 C-18 (ODS) column and the solvent system used was a gradient comprising of (A) acetonitrile and (B) water with a flow rate of 1 ml/min. The detection was performed using a PDA detector. Regression equation pertaining to all the bioactive isolates revealed a linear relationship (r2 > 0.9995). The detection limits (S/N = 3) ranged from 0.005 to 0.001 microg/ml. Of all the active isolates, sesamin was identified to be present in maximum quantities (0.91%) where as brachystamide B was found in minimum quantity (0.01%).
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PMID:HPLC assisted chemobiological standardization of alpha-glucosidase-I enzyme inhibitory constituents from Piper longum Linn-An Indian medicinal plant. 1687 68

2-Deoxy-2-fluorosalacinol and a 1,2-ene derivative of the naturally occurring glycosidase inhibitor salacinol were synthesized for structure activity studies with human maltase glucoamylase (MGA). 2-Deoxy-2-fluorosalacinol was synthesized through the coupling reaction of 2-deoxy-2-fluoro-3,5-di-O-p-methoxybenzyl-1,4-anhydro-4-thio-D-arabinitol with 2,4-O-benzylidene-l-erythritol-1,3-cyclic sulfate in hexafluoroisopropanol (HFIP) containing 0.3 equiv of K(2)CO(3). Excess of K(2)CO(3) resulted in the elimination of HF from the coupled product, and the formation of an alkene derivative of salacinol. Nucleophilic attack of the 1,4-anhydro-4-thio-D-arabinitol moiety on the cyclic sulfate did not proceed in the absence of K(2)CO(3). No reaction was observed in acetonitrile containing K(2)CO(3). The target compounds were obtained by deprotection with TFA. The 2-deoxy-1-ene derivative of salacinol and 2-deoxy-2-fluorosalacinol inhibited recombinant human maltase glucoamylase, one of the key intestinal enzymes involved in the breakdown of glucose, with an IC(50) value of 150 microM and a K(i) value of 6+/-1 microM, respectively.
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PMID:Synthesis of 2-deoxy-2-fluoro and 1,2-ene derivatives of the naturally occurring glycosidase inhibitor, salacinol, and their inhibitory activities against recombinant human maltase glucoamylase. 1829 54

An HPLC-UV method has been developed for the determination of valibose, miglitol, voglibose and acarbose, the four anti-diabetic drugs. The separation was accomplished successfully by using reversed phase chromatography (Prevail carbohydrate column, 250 mm x 4.6 mm, 5 microm) with a gradient acetonitrile-phosphate buffer solution (pH 8.0) at a wavelength of 210 nm. Furthermore, the method of a high-performance liquid chromatography coupled with ESI-MS in positive ionization mode has been established. These two methods were successfully applied to the assay and qualitative detection of four alpha-glucosidase inhibitors in the potential counterfeit anti-diabetic drugs.
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PMID:Development and validation of HPLC-UV-MS method for the control of four anti-diabetic drugs in suspected counterfeit products. 2134 24