The preparation of ribonucleic acid from yeast, tobacco leaves and tobacco mosaic virus

Abstract
Most of the nucleic acid in suitably prepared extracts from yeast, tobacco-leaf microsomes and tobacco mosaic virus (TMV) can be precipitated at pH 3-4 by NaCl. A small part of the nucleic acid in commercial products can also be precipitated. Preparations of nucleic acid made from yeast in this way appear to have a high mean particle weight and to contain less than 1% of protein. Their contents of Ca, Fe and Mg are low and probably the result of contamination. Those from TMV contain significant amounts of deoxyribose nucleic acid but the other 2 are substantially free from it.