These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: The Na(+)-dependent proline carrier, of eel intestinal brush-border membrane, sequentially binds proline and then Na+.
    Author: Maffia M, Cassano G, Marcucci D, Vilella S, Storelli C.
    Journal: Biochim Biophys Acta; 1990 Aug 10; 1027(1):8-16. PubMed ID: 2397223.
    Abstract:
    The mechanism of Na+/L-proline cotransport, present on brush-border membrane (BBM) vesicles of the European eel intestine, was studied. Initial cotransport rates, depending on increasing proline and Na+ concentrations in the extravesicular medium (zero-trans conditions), were measured by monitoring the decay of an inside-negative membrane potential, i.e. the fluorescence quenching of the voltage-sensitive cyanine dye 3,3'-diethylthiacarbocyanine iodide (DiS-C2(5)). By simultaneously estimating the substrate-dependent Na(+)-influx (with the fluorescent dye) and the Na(+)-dependent [3H]substrate influx, it was concluded that proline was cotransported with 1 Na+ ion and glucose with 2 Na+ ions. The kinetics of proline/Na+ cotransport were then investigated. Graphical analysis excluded a ping-pong mechanism. Under rapid equilibrium assumptions, by fitting model equations to rate values it was possible to exclude the random and the ordered Na+/proline mechanisms. Therefore, in eel intestinal BBM vesicles, the mechanism of proline/Na+ cotransport is ordered and prolineout binds to the carrier prior to Na+out.
    [Abstract] [Full Text] [Related] [New Search]