Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Rat intestinal maltase-glucoamylase was purified in the presence of detergent and proteolytic inhibitors, and the 130000 and 145000 subunits were separated and isolated by preparative sodium dodecyl sulfate - polyacrylamide gel electrophoresis and electrophoretic elution. Amino acid analyses were very similar, with a small excess of apolar amino acid residues in the 145000 subunit. Peptide mapping with Staphylococcus aureus V8 protease revealed eight similar peptide products for each, with apparent elongation of the five larger peptides in the 145000 subunit by a relative mass (Mr) of 2000-5000. alpha-Chymotrypsin maps showed at least eight identical cleavage products plus one large, shared product which was larger by a Mr of 5000 in the 145000 subunit. Cyanogen bromide cleavage of the 145000 subunit produced a single peptide of Mr 75000. A peptide of Mr 66000, also indicative of a central cleavage, was generated from the 130000 subunit, but a second cleavage into 43000 and 23000 segments was also evident. Several sets of antibodies formed against both antigens consistently gave reactions of identity without spurring on immunodiffusion. These results indicate extreme homology between the central segment of the 145000 subunit and the 130000 subunit. The cyanogen bromide cleavage results suggest, however, that the two central sequences are not absolutely identical and therefore that one subunit may not be a posttranslational derivative of the other.
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PMID:Mapping of proteolytic and cyanogen bromide peptides from subunits of intestinal maltase-glucoamylase: evidence for significant homology. 392 86

The ability of eight stripping agents to solubilize five marker enzymes from rat renal brush border membranes isolated by three different preparative methods was examined. Protein and enzyme activities - alkaline phosphatase (APase), L-leucine aminopeptidase (LAPase), gamma-glutamyl transpeptidase (GGTase), gamma-glutamyl hydrolase (GGHase) and maltase - solubilized by the treatments were expressed as percent of total activity recovered in excess of control values. The relative enzyme activity and the solubilization factor were determined for each marker enzyme in every treated sample and the treatments with the eight agents compared. Trypsin treatment released > 80% of LAPase and < 10% of total membrane protein. Papain treatment released only 16--23% of total membrane protein but most of the enzyme activities except APase. Neuraminidase had no solubilizing effect. 4--10% of total membrane protein was solubilized by LiCl treatment but no marker enzyme activities were released. Less total membrane protein was released by treatment with proteolytic enzymes or LiCl than with the detergents Triton X-100, hexadecyltrimethylammonium bromide, sodium deoxycholate, and sodium dodecylsulfate. APase activity was the least readily solubilized. Correlating the degree of solubilization for five marker enzymes with the types of stripping agents used and with the appearance of the membrane surface when examined by electron microscopy led to the suggestion that LAPase, GGTase, GGHase and maltase molecules are part of an interwoven surface layer of membrane proteins which can be disrupted by transamidation and transesterification reactions. APase appears to be more strongly associated with the intact lipid matrix than the bulk of the membrane protein.
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PMID:Ease of solubilization of five marker enzymes in three preparations of rat renal brush border membranes. 610 74

Two membrane proteins, maltase and gp330 (the pathogenic antigen of Heymann nephritis), present in the proximal tubule brush border have recently been independently purified and found to be large glycoproteins of similar molecular weight (Mr = approximately 300,000) by SDS PAGE. To determine the relationship between the two, monoclonal antibodies raised against the purified proteins were used for comparative immunochemical analyses and immunocytochemical localization. When a detergent extract of [35S]methionine-labeled rat renal cortex was used for immunoprecipitation with monoclonal antimaltase IgG, a single band of approximately 300 kdaltons was precipitated, whereas a single 330-kdalton band was precipitated with monoclonal anti-gp330 IgG. Monoclonal antimaltase (gp300) IgG also immunoprecipitated maltase activity from solubilized renal maltase preparations, whereas monoclonal anti-gp330 IgG failed to do so. When cyanogen bromide-generated peptide maps of the two proteins were compared, there were many similar peptides, but some differences. When maltase and gp330 were localized by indirect immunofluorescence and by indirect immunoperoxidase and immunogold techniques at the electron microscope level, they were found to be differently distributed in the brush border of the initial (S1 and S2) segments of the proximal tubule: maltase was concentrated (approximately 90%) on the microvilli, and gp330 was concentrated (approximately 90%) in the clathrin-coated apical invaginations located at the base of the microvilli. We conclude that maltase (gp300) and the Heymann nephritis antigen (gp330) are structurally related membrane glycoproteins with a distinctive distribution in the proximal tubule brush border which may serve as markers for the microvillar and coated microdomains, respectively, of the apical plasmalemma.
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PMID:Microdomains of distinctive glycoprotein composition in the kidney proximal tubule brush border. 637 Oct 23

The sites of glycosylation of Chinese hamster ovary cell expressed testicular angiotensin-converting enzyme (tACE) have been determined by matrix-assisted laser desorption ionization/time of flight/mass spectrometry of peptides generated by proteolytic and cyanogen bromide digestion. Two of the seven potential N-linked glycosylation sites, Asn90 and Asn109, were found to be fully glycosylated by analysis of peptides before and after treatment with a series of glycosidases and with endoproteinase Asp-N. The mass spectra of the glycopeptides exhibit characteristic clusters of peaks which indicate the N-linked glycans in tACE to be mostly of the biantennary, fucosylated complex type. This structural information was used to demonstrate that three other sites, Asn155, Asn337, and Asn586, are partially glycosylated, whereas Asn72 appears to be fully glycosylated. The only potential site that was not modified is Asn620. Sequence analysis of tryptic peptides obtained from somatic ACE (human kidney) identified six glycosylated and one unglycosylated Asn. Only one of these glycosylation sites had a counterpart in tACE. Comparison of the two proteins reveals a pattern in which amino-terminal N-linked sites are preferred. The functional significance of glycosylation was examined with a tACE mutant lacking the O-glycan-rich first amino-terminal 36 residues and truncated at Ser625. When expressed in the presence of the alpha-glucosidase I inhibitor N-butyldeoxynojirimycin and treated with endoglycosidase H to remove all but the terminal N-acetylglucosamine residues, it retained full enzymatic activity, was electrophoretically homogeneous, and is a good candidate for crystallographic studies.
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PMID:Identification of N-linked glycosylation sites in human testis angiotensin-converting enzyme and expression of an active deglycosylated form. 901 98

Synthesis of beta-maltosides, p-nitrophenyl-beta-D-maltoside and 4-methylumbelliferyl-beta-D-maltoside, based on interaction of hepta-acetate-beta-D-maltosyl fluoride with the corresponding trimethylsilyl ethers of p-nitrophenol and 4-methylumbelliferone is described. 2-Chloro-4-nitrophenyl-beta-D-maltoside was synthesized by interaction of hepta-acetate-alpha-D-maltosyl bromide with 2-chloro-4-nitrophenol in two phase system using phase transfer catalyst. The method of assay of neutral alpha-glucosidase from human kidney and urine using synthesized beta-maltosides (p-nitrophenyl-beta-D-maltoside, 2-chloro-4-nitrophenyl-beta-D-maltoside and 4-methylumbelliferyl-beta-D-maltoside) as substrates and beta-glucosidase as an auxiliary enzyme is proposed. The method is simple, convenient and 10-fold more sensitive than the commonly used alpha-glucosidase assay procedure with the corresponding synthetic alpha-glucosides, p-nitrophenyl-alpha-D-glucoside and 4-methylumbelliferyl-alpha-D-glucoside. A modification of the method, with p-nitrophenyl-beta-D-maltoside as substrate, was applied to the semi-automatic assay of urinary alpha-glucosidase in 96-well microtitre plates.
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PMID:[Synthesis of beta-maltosides, derivatives of p-nitrophenol, 2-chloro-4-nitrophenol, and 4-methylumbelliferone, and their use as substrates for determining alpha-glucosidase activity]. 925 25

The primary amino group, the competitive inhibitor of maltase, was used as ligand and the enzyme was purified to homogeneity in a single step. The amino group affiants of ethylene (C2-NH2) and hexamethylene (C6-NH2) diamines were prepared by coupling to cyanogen bromide activated Sepharose CL-4B. The enzyme was quantitatively adsorbed at alkaline pH (pH 8.2), while the elution could be effected only in presence of maltose at acidic pH. The elution of enzyme by maltose was independent of spacer arms (C2 and C6) which suggests specific binding of the enzyme through inhibitor site.
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PMID:Affinity chromatography of maltase on aliphatic amines as ligands. 1038 13

The inhibitory effects of natural and synthetic inhibitors on the intestinal membrane-bound hydrolase, alpha-glucosidase (AGH), were evaluated by using an immobilized cyanogen bromide-activated Sepharose 4B support. Immobilized AGH (iAGH) inhibition study by synthetic inhibitors (acarbose and voglibose) revealed that the magnitude of inhibition differed from that in the free AGH (fAGH) study: IC50 value of acarbose in iAGH-maltase assay system, 340-430 nM; fAGH, 11 nM. iAGH-maltase inhibition by both inhibitors was influenced by blocking reagents with different functional groups (COOH, OH, CH3, and NH2 groups). On the other hand, significant iAGH-sucrase inhibitory activity was observed only when using the negatively charged support induced by 0.1 M beta-alanine. The Km values obtained in the iAGH assay system were similar to those from the fAGH method. With natural inhibitors, the iAGH-sucrase inhibitory activity of D-Xylose, with in vivo glucose suppression, increased twice compared to that in fAGH. Green tea extract gave almost the same inhibition for both AGH assay systems.
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PMID:Evaluation of alpha-glucosidase inhibition by using an immobilized assay system. 1099 9

Gateways to Clinical Trials is a guide to the most recent clinical trials in current literature and congresses. The data in the following tables has been retrieved from the Clinical Studies knowledge area of Prous Science Integrity, the drug discovery and development portal, http://integrity.prous.com. This issue focuses on the following selection of drugs: 81C6; Adefovir dipivoxil, Agalsidase alfa, AGM-1470, albumin interferon alfa, alefacept, alosetron hydrochloride, anakinra, anti-CTLA-4 Mab, aprepitant, aripiprazole, atazanavir; BAY-43-9006, BBR-3438, beta-L-Fd4C, bimatoprost, bortezomib, bosentanBR96-doxorubicin; Caspofungin acetate, ciclesonide, cilengitide, cilomilast, COL-1621, COL-3, CpG-7909, cyclosporine; DCVax-Brain, dexmethylphenidate hydrochloride, dexosome vaccine (melanoma), donepezil hydrochloride, drotrecogin alfa (activated), DTI-015, [99Tc]-DTPA-mannosyldextran, duloxetine hydrochloride; Emivirine, emtricitabine, entecavir, epothilone B, estradiol-MNP, etonogestrel/etonogestrel/ethinylestradiol, etoricoxib; Febuxostat, fondaparinux sodium, fosamprenavir calcium; Gefitinib, GVS-111; Heparinase I, HspE7, human alpha-glucosidase, human insulin; Imatinib mesylate, INGN-241, interferon alfa B/D hybrid, interferon alfa Biphasix, ISIS-14803; Lanicemine hydrochloride, 1311-lipiodol, liposome-encapsulated mitoxantrone, lixivaptan, lumiracoxib, lupus-AHP, LY-466700; Marimastat, MEN-10755, micafungin sodium; Nitronaproxen, NSC-683864 Omalizumab, oral insulin; Palonosetron hydrochloride, peginterferon alfa-2a, pimecrolimus, pralnacasan, pramlintide acetate, pregabalin, pyrazoloacridine; R-165335, ranolazine, risperidone, RPR-109881;, RSD-1235, Satraplatin, seocalcitol, sertindole, SMART anti-interferon gamma antibody, sulfasalazine; T-138067, TAK-013, tegaserod maleate, telithromycin, tenofovir disoproxil fumarate, teriparatide, tiotropium bromide, tipifarnib, TP-38; Valdecoxib, vatalanib succinate, voriconazole; ZD-9331.
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PMID:Gateways to clinical trials. 1269 Jul 8

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