Figure 5: Effect of elevated pressure on the rate of cross-link reversal; percentage of monomeric protein recovered. 1 mg/ml solutions of RNase A was incubated in 10% phosphate buffered formalin for one hour, and the excess formaldehyde solution was exchanged for 1 X TAE buffer, pH 4. The aqueous fixed RNase A solution consisted of 18 percent monomeric and 82 percent multimeric protein by 1-D SDS-PAGE. Aliquots of the formalin fixed solution were incubated at 14.7–40,000 psi for 3.5 hr at either 55°C (squares) or 65°C (triangles). The heat-treated samples were separated by SDS-PAGE and the gel bands were integrated to determine the percentage of monomeric protein at each pressure.