Nuclear Proteins of Tumors and Other Tissues: A Review^* Free

Nuclear proteins have been separated into lipoproteins, globulins, and “arginine-rich” histones, and “lysine-rich” histones. These histones are the most extensively characterized of the nuclear proteins, having been assayed for amino acid content, molecular weight, solubility characteristics, and sedimentation properties. A variety of methods, including differential precipitation, electrophoresis, ultracentrifugation, and chromatographic analysis, has unequivocally established the existence of the two types of histones, and in some instances as many as six have been found. Recently, studies have been carried out on metabolism of histones of neoplastic and non-neoplastic tissues with radioactive amino acids as precursors; these have indicated a higher rate of labeling of histones of neoplastic tissues than of nontumor tissues. However, significant and consistent differences in composition and physical properties have not yet been demonstrated for histones or other nuclear proteins of tumors and other tissues. Much study is necessary to establish the role of the nucleus in cellular metabolism.