Premium
Sodium‐dependent Transport of [ 3 H](1 d ) chiro ‐Inositol by Tetrahymena
Author(s) -
KERSTING MICHAEL C.,
RYALS PHILLIP E.
Publication year - 2004
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/j.1550-7408.2004.tb00571.x
Subject(s) - inositol , biology , tetrahymena , sodium , inositol phosphate , cytochalasin b , biochemistry , inositol trisphosphate , chemistry , receptor , cell , organic chemistry
ABSTRACT. The transport characteristics of (1D) chiro ‐inositol by the ciliate Tetrahymena were examined in competition studies employing [ 3 H](1D) chiro ‐inositol. (1D) chiro ‐inositol transport was competed by unlabeled (1D) chiro ‐inositol, myo ‐inositol, scyllo ‐inositol, and D‐glucose in a concentration‐dependent manner. Conversely, (1D) chiro ‐inositol competed for [ 3 H] myo ‐ and [ 3 H] scyllo ‐inositol transport. Lineweaver‐Burke analysis of the competition data indicated a K m of 10.3 mM and a B max of 4.7 nmol/min/mg for (1D) chiro ‐inositol. Transport of (1D) chiro ‐inositol was inhibited by cytochalasin B, an inhibitor of facilitated glucose transporters, and phlorizin, an inhibitor of sodium‐dependent transporters. Removal of sodium from the radiolabeling buffer also inhibited uptake. The presence of 0.64 mM calcium or magnesium ions exerted negligible effects on transport, although potassium was inhibitory. [ 3 H](1D) chiro ‐Inositol was shown to be incorporated into Tetrahymena phosphoinositides.