Phase separation of integral membrane proteins in Triton X-114 solution.

TLDR

Triton X‑114 forms a homogeneous solution at 0 °C but undergoes temperature‑dependent phase separation into aqueous and detergent phases above 20 °C, with the extent influenced by other surfactants. This study investigates how proteins partition during Triton X‑114 phase separation. Membranes and whole cells are solubilized with Triton X‑114, and the resulting soluble material is subjected to phase separation. Hydrophilic proteins remain exclusively in the aqueous phase, whereas amphiphilic integral membrane proteins partition into the detergent phase, allowing their separation and identification from crude extracts.

Abstract

A solution of the nonionic detergent Triton X-114 is homogeneous at 0 degrees C but separates in an aqueous phase and a detergent phase above 20 degrees C. The extent of this detergent phase separation increases with the temperature and is sensitive to the presence of other surfactants. The partition of proteins during phase separation in solutions of Triton X-114 is investigated. Hydrophilic proteins are found exclusively in the aqueous phase, and integral membrane proteins with an amphiphilic nature are recovered in the detergent phase. Triton X-114 is used to solubilize membranes and whole cells, and the soluble material is submitted to phase separation. Integral membrane proteins can thus be separated from hydrophilic proteins and identified as such in crude membrane or cellular detergent extracts.