Abstract
Mitochondria were rapidly prepared from rat liver by differential centrifugation. Nucleic acids were extracted by a detergent-phenol method and the DNA and RNA were separated by hydroxyapatite chromatography. Mitochondrial DNA thus prepared contained up to 90% of the un-nicked, twisted, circular form-I, as determined by sedimentation velocity experiments. The mitochondrial DNA was shown to be free of nuclear DNA by its renaturation properties and by its banding pattern in an alkaline cesium chloride equilibrium buoyant-density gradient. Both early-melting and delayed-melting transitions were observed, presumably resulting from thermal denaturation of the intact circular mitochondrial DNA. The form-I mitochondrial DNA was rapidly nicked at pH 12.3 in 3 m-CsCl solution. Upon centrifugation to equilibrium, the two mitochondrial DNA strands separated and banded at 1.740 and 1.771 g/ml. However, a small fraction of the closed-circular form-I was stable enough at 25 °C and pH 12.3 to form a band at a buoyant density of 1.766 g/ml.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
