Western blot showing native (A) and recombinant rat (rr) ALR (B). (A) Proteins extracted from the rat liver were separated under non-reducing (control- CT) or reducing (25 mM dithiothreitol: DTT) conditions on a SDS-PAGE. The separated proteins were transferred to Immobilon-P membrane (Millipore, Bedford, MA, USA), and ALR was detected with anti-rrALR Ab and ECL kit (Amersham, UK) . (B) The rrALR was subjected to SDS-PAGE under nonreducing (CT) or reducing (DTT or 5% 2-mercaptoethanol: 2-ME). While all of the high molecular weight ALR species (38 to 42 kDa) migrate as a single 22-kDa protein under reducing condition (A), rr-ALR migrates as a single 22-kDa protein both under reducing and non-reducing conditions.