The article describes a rapid alkaline extraction procedure for preparing recombinant plasmid DNA from bacterial cells. The method is designed to be simple and efficient, allowing for the analysis of 100 or more clones per day using gel electrophoresis. The key principle involves selective alkaline denaturation of high molecular weight chromosomal DNA while covalently closed circular (CCC) DNA remains double-stranded. The pH control is achieved without a pH meter by using glucose as a buffer. Upon neutralization, chromosomal DNA renatures and forms an insoluble clot, leaving plasmid DNA in the supernatant. This method has been successfully applied to extract both large and small plasmid DNAs. The procedure is versatile, suitable for screening many small samples and producing plasmid DNA that can be digested by restriction enzymes or used for transforming other cells. The article also includes detailed materials and methods, results, and discussions, demonstrating the effectiveness and reliability of the method.The article describes a rapid alkaline extraction procedure for preparing recombinant plasmid DNA from bacterial cells. The method is designed to be simple and efficient, allowing for the analysis of 100 or more clones per day using gel electrophoresis. The key principle involves selective alkaline denaturation of high molecular weight chromosomal DNA while covalently closed circular (CCC) DNA remains double-stranded. The pH control is achieved without a pH meter by using glucose as a buffer. Upon neutralization, chromosomal DNA renatures and forms an insoluble clot, leaving plasmid DNA in the supernatant. This method has been successfully applied to extract both large and small plasmid DNAs. The procedure is versatile, suitable for screening many small samples and producing plasmid DNA that can be digested by restriction enzymes or used for transforming other cells. The article also includes detailed materials and methods, results, and discussions, demonstrating the effectiveness and reliability of the method.