The use of bovine serum albumin (BSA) in routine biochemical assays such as restriction enzyme digestion and immunodetection is plagued largely by two common contaminants, DNase and immunoglobulins G (IgGs). Acetylation of BSA to inactivate DNase limits its use as a protein standard due to interference with color development in assays such as Lowry's. In spite of the availability of inexpensive BSA, its purification involves several cumbersome and time-consuming steps. In this work, we employed a modified strategy of ammonium sulfate precipitation coupled with liquid chromatography to purify BSA that is free of DNase and IgGs. Purified BSA tested negative for the presence of DNase and IgGs using DNase and immunodetection assays respectively. We conclude that carefully controlled ammonium sulfate precipitation and liquid chromatography techniques are sufficient to purify BSA suitable for most routine laboratory applications. This purification strategy can yield more than 40 g BSA per liter of serum.
Keywords: Bovine serum albumin, ammonium sulfate, nuclease, purification, immunoglobulin G, chromatography