Some components of tobacco mosaic virus preparations made in different ways

Abstract

Part of the phosphorus in many tobacco mosaic virus preparations becomes soluble in trichloroacetic acid when the preparations are incubated. There is evidence that this is caused by the fission of normal leaf nucleoprotein by ribonuclease. Some steps in the purification remove the normal nucleoprotein but other properties of the virus, notably its precipitability by ammonium acetate, are altered at the same time. Plant ribonuclease is difficult to remove and it is detectable in all preparations. The smallest amount is found in those leaves that have been ultra-centrifuged from salt solutions in the presence of nucleic acid. Tobacco mosaic virus that has been denatured by trichloroacetic acid is a particularly sensitive system for detecting this residual nuclease.