DINESH YADAV AND N.K. SINGH
Abstract
Storage conditions for competent cells for carrying out routine transformation of E. coli using CaC12 method with plasmids of different size were optimized. Competent cells prepared by CaC12 method consistently gave transfr -mation efficiency of 2.8-2.4 x 106 transformants/pg of plasmid DNA when kept at 4°C in freeze upto 3 weeks. The efficiency of transformation was more or less same for plasmic-is of different sizes. Competent cells stored at 20°C was not very effective for long duration.