Biochemical characterization and purification of the neuronal sodium-dependent noradrenaline transporter.

The protein properties of the neuronal sodium-dependent noradrenaline (NA) transporter of PC12 (rat pheochromocytoma) cells and of bovine adreno-medullary cells were studied by means of binding of 3H-desipramine (3H-DMI). 3H-DMI binding was decreased by proteases, phospholipase A2, by disulfide reducing agents and by the sulfhydryl-group alkylating agent N-ethylmaleimide. The NA transporter was partially purified by anion exchange and affinity chromatography. Tritiated desmethylxylamine (3H-DMX) bound irreversibly and in a DMI-sensitive manner to two PC12 membrane proteins (32kd and 53kd) which may represent components of the NA transporter.