Preparation of Plasmid DNA Using Alkaline Lysis

There are probably as many “miniprep” recipes as there are laboratories doing molecular biology. The following protocol is derived from the alkaline lysis recipe originally described by Birnboim and Doly (1 ), which was slightly modified in the 1982 edition of Moleculur Cloning: A Laboratory Manual (2 ). This technique relies of the lysing of bacteria by sodium hydroxide and SDS, followed by neutralization with a high concentration of potassium acetate, which results in the selective precipitation of the bacterial chromosomal DNA and other high-mol-wt cellular structures. The plasmid DNA, which stays in suspension, is then precipitated with isopropanol.