Isolated RNA is run on a denaturing polyacrylamide gel. It is essentially a combination of denaturing RNA gel electrophoresis, and a blot. Unlike denaturing methods, native gel electrophoresis does not use a charged denaturing agent. Methyl isobutyl ketone is also used as a denaturing agent for denatured alcohol. SDS-PAGE is generally used for the denaturing electrophoretic separation of proteins. This solubilises the hydrophobic region in the solution, thereby denaturing the protein. Some species of halobacteria have acidic proteins that resist the denaturing effects of salts. Denaturing conditions are necessary for proper estimation of molecular weight of RNA. Guanidinium thiocyanate is also used for its denaturing effect on various biological samples. Sodium dodecyl sulfate (SDS) interacts with proteins, denaturing them, and giving them a negative charge. A cloudy ring forms where the substances meet, indicating the acids are denaturing the proteins. This lower temperature process prevents the decomposition and denaturing of compounds. A randomly coiled state for any polypeptide chain can be attained by denaturing the system. Potassium nitrate is believed to prevent the protein from denaturing in the acidic milieu. The same transformation can be effected with a denaturing chemical.