Substrate recognition and translocation by polyspecific organic cation transporters

Biol Chem. 2011 Jan;392(1-2):95-101. doi: 10.1515/BC.2011.009.


Organic cation transporters (OCTs) of the SLC22 family play a pivotal role in distribution and excretion of cationic drugs. They mediate electrogenic translocation of cations in both directions. OCTs are polyspecific transporters. During substrate translocation they perform a series of conformational changes involving an outward-facing conformation, an occluded state and an inward-facing conformation. Mutagenesis of OCT1 in combination with homology modeling showed that identical amino acids form the innermost parts of the outward-open and inward-open binding clefts. In addition to low affinity substrate binding sites, OCT1 contains high affinity substrate binding sites that can mediate inhibition via non-transported compounds.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Binding Sites
  • Organic Cation Transport Proteins / chemistry
  • Organic Cation Transport Proteins / metabolism*
  • Protein Transport
  • Substrate Specificity


  • Organic Cation Transport Proteins