Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: KEGG:D02259 (NaI)
 1,823 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The [3H] phlorizin-binding component of brush border vesicles was enriched in situ by negative purification. Several procedures, known to effect selective solubilization of membrane components, were used separately or in combination to remove proteins unrelated to the binding. Deoxycholate ruptured the vesicles and released 67% of their protein, thereby increasing the specific [3H] phlorizin-binding activity of the pellet three-to fourfold. Extracting the deoxycholate-pellets with either NaI or alkaline solutions released up to 38% of the deoxycholate-insoluble protein without significantly affecting phlorizin binding. The polypeptide composition of the membranes at the different stages was analyzed by NaDodSO4-polyacrylamide gel electrophoresis. A number of polypeptides present in the original vesicles could be ruled out as essential components of the [3H] phlorizin binding entity. Intact and deoxycholate-treated vesicles were subjected to proteolytic attack. Papain liberated sucrase and isomaltase from intact vesicles, but affected neither other Coomassie-stained bands nor phlorizin binding. Neither the protein composition nor the binding properties of sealed vesicles were influenced by trypsin or chymotrypsin. However, all the proteolytic enzymes tested on deoxycholate-treated membranes substantially reduced [3H] phlorizin binding and produced concomitantly the disappearance of several bands from the electrophoretic profile. Pretreatment of vesicles with papain, followed by deoxycholate extraction and incubation in alkaline media, increased the specific binding activity of the membranes up to ninefold by removing close to 90% of the protein. A limited number of polypeptides are suggested as possible candidates for the glycoside-binding site of intestinal brush borders.
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PMID:Partial purification of the sugar carrier of intestinal brush border membranes. Enrichment of the phlorizin-binding component by selective extractions. 52 29

About 90% of the protein of hamster intestinal brush borders was solubilised in 0.25% (w/v) sodium dodecyl sulphate without total loss of biological activity. Detergent-polyacrylamide gel electrophoresis of the solubilised proteins separated 10-15 bands and partially resolved maltase, lactase, sucrase-maltase, trehalase and alkaline phosphatase activities. The disaccharidases, which were associated with the higher molecular weight proteins, were preferentially solubilised with 0.1%. (w/v) Triton X-100, butanol or papain, whereas Tris and NaI extracted only the lower molecular weight proteins, possible derived from the core filaments. Electrophoresis of brush border proteins metabolically labelled with [14-C] glucosamine suggested that many of the membrane-bound enzymes are glycoproteins. However, chromatography of a papain digest on Sephadex G-200 showed that the sucrase-maltase complex can be separated nearly free of carbohydrate without total loss of activity. The importance of characterizing membrane proteins solubilised by a number of techniques is discussed.
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PMID:Solubilization of brush borders of hamster small intestine and fractionation of some of the components. 113 70

An antigen-specific method has been developed for direct detection and quantitation of HBsAg-ICs. The method involves (1) precipitation of HBsAg-ICs with 3.5% PEG; (2) dissociation of the PEG precipitated ICs by treatment with NaSCN, NaI, KBr, low or high pH buffers, trypsin or papain; and (3) detection and titration of HBsAg and/or anti-HBs liberated from ICs. Treatment with 2 M and 3 M NaSCN, papain or trypsin liberates HBsAg, while following treatment with 3 M and NaI free anti-HBs is detectable. Trypsin digestion (2 mg/ml, 30 min at 37 degrees C) proved to be most effective for disrupting HBsAg-ICs formed at equivalence as well as in excess of antigen or antibody. After trypsin digestion of the sample RPHA, RIA and ELISA may be used as a third step. Th
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PMID:Detection and quantitation of hepatitis-B surface antigen immune complexes (HBsAg-ICs) by an antigen-specific method. I. Detection and quantitation of in vitro prepared HBsAg-ICs. 615 46