BASE COMPOSITIONAL ANALYSIS OF NANOGRAM QUANTITIES OF UNLABELED NUCLEIC-ACIDS

After conversion of unlabeled DNA and RNA to 3′-mononucleotides accurate base compositional analysis can be performed on as little as 10 ng of the hydrolysate. The 3′-mononucleotides are first quantitatively postlabeled with [γ-32P]ATP by T4 polynucleotide kinase and are then separated as mononucleoside diphosphates on Whatman DE-81 ion-exchange paper at pH 3.5 after hydrolysis of surplus [γ-32P]ATP to 32P1. The locations of the four labeled nucleoside diphosphates are determined by autoradiography and the ratio of radioactivity in the four spots gives the base ratio of the sample. © 1979 Academic Press, Inc.