Sodium-dependent Transport of [3H](1d)chiro-Inositol by Tetrahymena

• Published in: The Journal of eukaryotic microbiology Vol. 51; no. 3; pp. 307 - 311
• Main Authors: Kersting, Michael C, Ryals, Phillip E
• Format: Journal Article
• Language: English
• Published: 01.05.2004
• Subjects: Tetrahymena
• ISSN: 1066-5234; 1550-7408
• DOI: 10.1368/1066-5234(2004)051<0307:STOHBT>2.0.CO;2

The transport characteristics of (1D)chiro-inositol by the ciliate Tetrahymena were examined in competition studies employing [3H](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 [3H]myo- and [3H]scyllo-inositol transport. Lineweaver-Burke analysis of the competition data indicated a Km of 10.3 mM and a Bmax 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. [3H](1d)chiro-Inositol was shown to be incorporated into Tetrahymena phosphoinositides.