Why do solutions containing SDS form precipitates?
SDS is a detergent used to denature proteins leading to disruption of cell membranes and dissociation of nucleic acid-protein complexes in DNA and RNA extractions. It tends to come out of solution at concentrations of 10% or greater, especially at low temperatures or in high-salt buffers. SDS can be resolubilized by slowly heating the solution to 65°C with slight agitation.