Chromosomal proteins of Sarcoma 180 ascites tumor cells isolated by the method of Johns contain approximately one weight of histone proteins per weight of DNA. The histone proteins consist of five major fractions which are present in different molar r...
Chromosomal proteins of Sarcoma 180 ascites tumor cells isolated by the method of Johns contain approximately one weight of histone proteins per weight of DNA. The histone proteins consist of five major fractions which are present in different molar ratios to those of higher eucaryotes. These histone fractions were also compared with respect to their electrophoretic mobility on acrylamide disc gel, amino acid composition and side-chain modification. The tumor-specific side-chain modification was noted with histone fraction Hl which contains an unusual methylderivative of histidine residue, 3-N-methylhistidine. It was also found that histone fractions H2a, H3 and H4 contain detectable amounts of ε-N-monomethyllysine.