A carrier-mediated, Na+ gradient-dependent transport for biotin in human intestinal brush-border membrane vesicles

作者: H. M. Said , R. Redha , W. Nylander

DOI: 10.1152/AJPGI.1987.253.5.G631

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摘要: Transport of biotin across human intestinal brush-border membrane (BBM) was examined using vesicle (BBMV) technique. Uptake by BBMV is mostly the result transport substrate into an active intravesicular space with little binding to surfaces. The carrier mediated and 1) Na+ (but not K+) gradient dependent a distinct "over-shoot" phenomenon, 2) saturable as function concentration in presence apparent Km Vmax for gradient-dependent system 5.26 microM 13.47 pmol.mg protein-1.20 s-1, respectively, 3) inhibited structural analogues related compounds. Unlike electrogenic D-glucose, anionic (out greater than in) affected imposing relatively positive electrical potential, suggesting that most likely electroneutral process. These results demonstrate existence carrier-mediated BBM show process electrically silent. It suggested driven probably through biotin-Na+ cotransport system.

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