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 microvillus maltase-glucoamylase was isolated by detergent extraction and purification in the presence of protease inhibitors as previously described and incorporated into phospholipid vesicles. After purification of the vesicles on Sephadex G-50, maltase was labelled with 3-trifluoromethyl-3-(m-[125I]iodophenyl) diazirine ([125I]TID) by photolysis using a water-jacketed mercury vapour lamp with a saturated CuSO4 filter. The labelled enzyme was extracted with acetone, resuspended in 1% Triton X-100, reincorporated into phospholipid vesicles, and digested with activated papain to release the hydrophilic polar head of the enzyme from the vesicle bilayer. Vesicle-bound and free enzyme components were separated on Sepharose 4B. Ninety percent of the enzymatic activity was free, while a similar percentage of radioactive label remained with the vesicles in keeping with the separation of an active polar headpiece from a labelled apolar peptide in the lipid bilayer. The vesicle fractions were subjected to chromatography on Sephadex LH-60 with ethanol--formic acid (7:3) as the eluant. A single radioactive peak (14 kilodaltons (kDa)) was separated from labelled lipid. Sodium dodecyl sulfate--polyacrylamide gel electrophoresis of the peak showed a radioactive doublet of 26-28 kDa, possibly representing a dimer. No other labelled peptides were found. These results suggest that detergent-solubilized maltase-glucoamylase is inserted into the phospholipid bilayer via an apolar peptide with a minimum molecular mass of 14 kDa. The peptide probably represents a terminal anchor segment of the 145-kDa subunit which is converted to 130 kDa when the membrane-bound enzyme is solubilized by papain.
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PMID:Hydrophobic binding domains of rat intestinal maltase-glucoamylase. 309 59

The inhibitory properties of bromoacetyl-p-aminohippuric acid as the affinity probe of the organic anion transport system were studied. Bromoacetylated p-aminohippurate was shown to be able to inhibit irreversibly the p-aminohippurate (PAH) uptake in brush-border membrane vesicles. The inhibition depends on both the time of treatment and the affinity probe concentration. The treatment of brush-border membrane with 1 mM bromoacetyl-p-aminohippurate for 1.5 h results in 100% irreversible inhibition of PAH transport but no changes were observed in the activity of alkaline phosphatase, gamma-glutamyltranspeptidase or maltase. The affinity labelling of the organic anion transporters was performed with bromoacetyl-p-amino[3H]hippuric acid. It was shown, by means of SDS-polyacrylamide gel electrophoresis, that the probe bound covalently to the brush-border membrane proteins with molecular masses of 28 kDa, 63 kDa, 98 kDa, and > 150 kDa. The data obtained with SITS and probenecid as the organic anion transport inhibitors indicate that brush-border membrane proteins of 28 kDa, 63 kDa, 98 kDa may correspond to the organic anion transport system.
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PMID:Affinity identification of organic anion transporters in brush-border membrane vesicles from rat kidney. 820 41

Evidence is presented for the existence of multiple proteins with antifungal and antiviral potency in cowpea seeds. The two proteins, designated alpha- and beta-antifungal proteins in accordance with their order of elution from the CM-Sepharose column, were capable of inhibiting human immunodeficiency virus (HIV) reverse transcriptase and one of the glycohydrolases associated with HIV infection, alpha-glucosidase, but beta-glucuronidase was not repressed. The ability of the proteins in retarding mycelial growth of a variety of fungi was also demonstrated with alpha-antifungal protein being more potent in most of the cases. Beta-antifungal protein was more active in only one instance. Both antifungal proteins had low cell-free translation-inhibitory activity. The proteins were adsorbed on Affi-gel blue gel-and CM-Sepharose but could be separated from one another during chromatography on the latter medium by means of a linear NaCl concentration gradient. Different molecular weights were exhibited by the proteins, being 28 kDa and 12 kDa respectively for alpha- and beta- antifungal proteins. Alpha-antifungal protein was characterized by an N-terminal sequence showing close resemblance to sequences of chitinases. Beta-antifungal protein exhibited an N-terminal sequence hitherto unknown in the literature.
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PMID:Structurally dissimilar proteins with antiviral and antifungal potency from cowpea (Vigna unguiculata) seeds. 1119 27