Solubilization of μ-opioid receptors enriched from bovine brain membranes

Abstract

Solubilization is the most critical step in the purification of opioid receptors as these proteins are highly sensitive to detergents and get inactivated even with very mild detergents. Membranes enriched with μ-opioid receptors from bovine corpus striatum were solubilized by various methods to obtain the active soluble receptor suitable for affinity purification.

Solubilization by digitonin resulted in marginal yields. CHAPS in presence of NaCl could extract active receptor into the solution. The detergent and NaCl were removed by either polyethylene glycol precipitation or by desalting on Sephadex G₅₀. The polyethylene glycol precipitation resulted in the formation of liposomes into which the receptor protein was

incorporated. Liposome formation was not observed in desalting method and the recovery of the receptor was partial.