Purification of kappa-opioid receptor subtype to apparent homogeneity from frog brain

Kappa-opioid receptor subtype was purified from digitonin solubilized preparation of frog brain membranes by hydrophobic and Sepharose 6B chromatography. 4800-fold purification over the membrane-bound receptors was achieved. The kappa receptor activity resides in a homo-oligomer of a single polypeptide of Mr 65,000.