Fig. 4. SDS–PAGE of the acetylcholine receptor purified from the numb fish N. tasmaniensis on the TDAC affinity column. Fractions 3, 5 and 7, correlating to the peak absorbance in Fig. 3A, were run on a 4–12% Bis-Tris NuPAGE gel and stained with Coomassie. The protein bands corresponding to the four subunits comprising the acetylcholine receptor are indicated on the right. The protein running between the and ß subunits is mostly likely the subunit, which is known to run as a doublet.