TABLE 3

Toxins that are substrates of human organic cation transporters

Charge of major microspecies at pH 7.4 was calculated with program MarvinSketch of ChemAxon; IC50 values are presented in brackets. Aflatoxin: Tachampa et al., 2008, ethidium: Lee et al., 2009, monocrotaline: Tu et al., 2013, paraquat: Chen et al., 2007, 2009b; Astorga et al., 2012.

Compound (Charge of Major Microspecies at pH 7.4) FunctionApparent Km (IC50) [µM]
hOCT1hOCT2hOCT3hMATE1hMATE2-K
Aflatoxin (0) mycotoxint (64)t (121)
Ethidium (+) mutagenic0.81.72
Monocrotaline (+) pneumotoxic25 (5.5)
Paraquat (++) toxic herbicidet114n.t.d.169a, 212a (51a)(16a)
  • n.t.d. no transport detected; t, transported.

  • a Uptake measurements performed in presence of an outwardly directed proton gradient.