Solubilization of [35S]lanthionine ketimine binding sites from bovine brain

Lanthionine ketimine (LK) binding sites were solubilized from bovine brain membranes using 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS) and Triton X-100. 10 mM CHAPS in 0.5 M potassium phosphate, pH 7.0, containing 20% glycerol was selected to solubilize LK binding entities. Some properties of CHAPS-solubilized LK binding sites have been studied. The CHAPS-solubilized preparation appeared to contain a homogenous population of binding sites for [35S]LK. Binding properties indicated that the solubilized binding sites were similar to the membrane-bound sites. [35S]LK specific binding was inhibited by other structurally related ketimines obtaining a similar rank order of inhibition for the soluble and the membrane-bound preparations. The successful solubilization of [35S]LK binding sites is a useful starting point for the purification of this binding protein.