The following plasmid DNA was prepared in low nuclease host bacteria and isolated through ion exchange chromatography. It is available in supercoiled form (ccc-form >95%) and, as a high-purity DNA (OD 260/280 > 1,70), it is ideal for different applications: Controlling transformation efficiency Comparison with plasmid ccc-forms of unknown size Cloning DNA-fragments Restriction (Preparing DNA-length markers) Calibrating DNA-separating or DNA-preparing processes or equipment Blocking DNA-chips with plasmid DNA of a defined sequence Plasmid DNA pUC19 lyophilized pUC19 is a standard high-copy cloning vector for E. coli recombinants. The position of the Multi Cloning Site (MCS), which is inserted in frame into the LacZ-gene, enables a blue-white selection of insert containing plasmid DNA by α-complementation. The copy number of plasmids per cell depends on the temperature and is approx. 70-80 at 37 °C and over 200 at 42 °C. General properties: OD 260/280 : >1,70 Genomic DNA: <2 % oc form: <3 % ccc form: >95 % Base pairs: 2686 Suitable for the blue / white selection