摘要：

An electrophoretic method has been developed for the analysis of ribonucleic acids (RNAs) ranging in size from 104 to 108 daltons. The method depends on the use of acrylamide gels strengthened with agarose for analysis of the larger RNAs. The resolving power of the method permitted individual characterization of RNAs in mixtures containing multiple species of RNA, without prior purification of each species; RNA molecules which differed in molecular weight by only a few per cent could be clearly distinguished, and the molecular weight of each estimated. This unusual application of electrophoretic methods for the determination of molecular weight is based on the observation that, for RNAs, smaller molecules migrate more rapidly than larger ones. The mobility and the logarithm of the molecular weight are inversely related and this relationship is approximately linear. The molecular weights estimated by this technique, although numerically dependent on values assigned to known RNA standards, are highly reproducible in gels of various composition, and are at present the best means of identification of species resolved by gel electrophoresis. By this means, liver 18S RNA is identified as a doublet of RNAs of 0.66 and 0.62 × 106 daltons and the analogous 16 S of Escherichia coli as a doublet of 0.58 and 0.54 × 106 daltons, while liver 5S RNA has a molecular weight of 38,000 daltons.

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