Potassium chloride is a widely used reagent in biochemistry and molecular biology. Potassium chloride is a salt commonly used in the preparation of phosphate buffered saline and for the extraction and solubilization of proteins. It is a good potassium source. Also used in the hypotonic KCl-propidium iodide protocol for univariate analysis of metaphase chromosomes; dissociation of eukaryotic ribosomes into subunits by high concentrations of potassium (0.3-1.0 M); preparation of mitochondria, provides an ionic osmotic support for those tissues that assume a gelatinous consistency upon homogenization.