Table 1. Dependence on internal substrate of the transport properties of proteoliposomes reconstituted with recombinant citrin, aralar1 or their C‐terminal domains (CTDs)
Internal substrateSubstrate transport (μmol/min/g protein)
CitrinCitrin CTDAralar1Aralar1 CTD
[14C]Aspartate[14C]Glutamate[14C]Aspartate[14C]Aspartate[14C]Glutamate[14C]Aspartate
None (Cl present)1.41.31.60.30.30.3
l‐Aspartate92.872.5178.425.217.140.5
l‐Glutamate55.390.3118.116.121.823.7
l‐Cysteinesulfinate81.265.9133.817.714.227.6
l‐Aminoadipate4.66.46.71.61.22.4
d‐Aspartate8.18.913.41.51.93.4
d‐Glutamate5.99.711.31.62.34.1
l‐Asparagine10.110.518.63.12.55.7
l‐Glutamine1.54.72.30.71.31.3
l‐Cysteate12.911.225.53.13.25.5
l‐Homocysteinesulfinate1.12.12.70.20.10.3
l‐Homocysteate1.82.04.50.10.30.9
Proteoliposomes were pre‐loaded internally with various substrates (concentration, 20 mM). Transport was started by the external addition of 50 μM [14C]aspartate or 200 μM [14C]glutamate and terminated after 30 s (citrin and its CTD) or 1 min (aralar1 and its CTD). Similar results were obtained in at least three independent experiments for each carrier investigated.