Sodium-dependent carnitine transport in human placental choriocarcinoma cells

Puttur D Prasad, Wei Huang, Sammanda Ramamoorthy, A. Lee Carter, Frederick H. Leibach, Vadivel Ganapathy

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

The JAR human placental choriocarcinoma cells were found to transport carnitine into the intracellular space by a Na+-dependent process. The transport showed no requirement for anions. The Na+-dependent process was saturable and the apparent Michaelis-Menten constant for carnitine was 12.3 ± 0.5 μM Na+ activated the transport by increasing the affinity of the transport system for carnitine. The transport system specifically interacted with L-carnitine, D-carnitine, acetyl-DL-carnitine and betaine. 6-N-Trimethyllysine and choline had little or no effect on carnitine transport. Of the total transport measured, transport into the intracellular space represented 90%. Plasma membrane vesicles prepared from JAR cells were found to bind camitine in a Na+-dependent manner. The binding was saturable with an apparent dissociation constant of 0.66 ± 0.08 μM. The binding process was specific for L-carnitine, D-carnitine, acetyl-DL-carnitine, and betaine. 6-N-Trimethyllysine and choline showed little or no affinity. It is concluded that the JAR cells express a Na+-dependent high-affinity system for carnitine transport and that the Na+-dependent high-affinity carnitine binding detected in purified JAR cell plasma membrane vesicles is possibly related to the transmembrane transport process.

Original languageEnglish (US)
Pages (from-to)109-117
Number of pages9
JournalBiochimica et Biophysica Acta - Biomembranes
Volume1284
Issue number1
DOIs
StatePublished - Oct 2 1996

Keywords

  • Carnitine
  • High-affinity binding
  • High-affinity transport
  • Human placenta
  • JAR choriocarcinoma cell
  • Plasma membrane

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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