Histone of calf thymus deoxyribonucleoprotein was isolated by three different methods: (1) Extraction from nucleoprotein solutions with dilute hydrochloric acid. (2) Extraction from cold saline nucleoprotein solutions with ethanol. (3) Salting out part of the histone, followed by removal of the nucleic acid from the remainder as an insoluble lanthanum salt. Similar yields were obtained in all cases. Measurements of fractional solubility, electrophoretic mobility, and sedimentation rate disclosed the presence of two principal components corresponding roughly to those obtained in the two stages of method (3). Alterations of one component were found to take place in aqueous solutions more alkaline than pH 4.0, resulting in the appearance of artifacts some of which sedimented more rapidly, while others sedimented more slowly, than the original material.
STUDIES OF THE ANOMALOUS TITRATION OF CALF THYMUS DESOXYPENTOSE NUCLEIC ACID AND NUCLEOHISTONE