Methods and reagents for purification of proteins

The present disclosure provides compositions and methods for purifying a protein such as DNase using a chromatographic process. The methods include a single chromatographic step and the use of high concentration salt buffers. The present disclosure provides methods for purification of a protein from a sample comprising loading the sample onto a chromatography column and washing the column with at least one buffer having very high conductivity. In some embodiments, the wash buffer has a conductivity of about 50 mS/cm, about 60 mS/cm, about 70 mS/cm, about 80 mS/cm, or higher. In further embodiments, the protein is eluted from the column with an elution buffer following the wash with the very high conductivity buffer.