The procedure for isolating DNA from mammalian tissues was evaluated in views of purity, yield and molecular nature and compared with the other conventional procedures. The present procedure is characterized by freezing the tissues at -55°C and rapid addition of organic deproteinizing agents in order to minimize the effect of endogenous DNase after tissue disruption. By conventional procedures, spooling out of the mammalian tissue DNA could scarcely be done, but it was possible to spool out DNA by the present procedure from bovine testis, spleen, pancreas, kidney and livers, with, for example, a typical yield of 16.6 mg of DNA from 10 gm of bovine testis. The isolated DNA's contained 0.5~1.8% of protein and 0.3~2.1% of RNA. DNA isolated from liver tissue among others contained significantly higher amounts of protein and RNA. It was made possible to improve the yield and purity of isolated DNA by adjusting the ratios of the amounts of tissues to the volumes of homogenizing solution, applying them differently to one sample after another. DNA's isolated by the present procedure were of double stranded nature, with comparable Tm values. The results suggest that the disruption of tissues by freeze-grinding and rapid addition of organic deproteinizing agents are very effective to inhibit the DNase activity, and that DNA preparations isolated after the present procedure meet the criteria required for various experiments.
|Number of pages||11|
|Journal||Korean Journal of Biochemistry|
|State||Published - 1 Jan 1981|