Partitioning of proteins in Triton X-114.

Abstract

Cultured mammalian cells and tissues can be solubilized by the nonionic detergent Triton X-114 (octylphenoxy polyethoxyethanol). This detergent, when in solution above its critical micelle concentration, increases its micelle weight when warmed from 0 to 20°C and in the process decreases its critical micelle concentration. This induces intermicellar interactions, which lead to turbidity (the cloud point) and phase separation of the detergent at 20°C. A simple low-speed centrifugation step recovers the detergent-enriched phase as an oily pellet. Following solubilization and warming to 20°C, integral membrane proteins partition into the detergent-enriched phase, and peripheral and cytosolic proteins are recovered from the detergent-depleted aqueous phase.