Sarcoma 180 복수암 세포에서 histone의 여러분획 즉 f1, f2a1, f2a2, f2b 및 f3로 분리 정제하여 in vitro에서 acetylation 및 methylation에 관한 연구를 행하였다. Methyl화 및 acetyl화의 관찰은 Sarcoma 180 복수암 세포의 핵을 L-methionine-Methyl-$^{14}C$ 또는 sodium acetate-1-$^{14}C$ 존재하에 jn vitro에서 행하였으며 histone 분획을 f1, f2a1, f2a2, f2b, 및 f3 별로 각각 추출 정제하였다. Methyl화 된 histone 분획들을 산으로 가수분해한 후 amino acid analyzer로 각 ammo 산을 각각 분리 정제하여 methyl화 또는 acetyl화한 amino 산 유도체 들을 동정 및 정량하였다. Histone을 methyl화 시킨 결과 polypeptide chain의 histidine 및 lysine 잔기의 유리 $epsilon$-amino group에 methyl근이 transfer 되었다. 각 histone 분획의 비활성은 f2a1이 가장 높았으며 f2b, f2a2, f3 및 f1의 순으로 방사능이 낮었다. $epsilon$-N-MethylIysine의 방사능을 histone의 여러 분획 즉 f1, f2a1, f2a2 및 f2b에서 증명하였으며 $epsilon$-N-dimethyllysine의 방사능이 $epsilon$-N-monomethyllysine 보다 1.7배나 많었다. Histone 분획 f2a2와 f2b에서는 3-methylhistidine에서도 방사능을 계측할 수 있었다. Whole histone의 각 분획에서 계측된 방사능의 값은 그 분획에서 분리한 $epsilon$-N-monomethyllysine, $epsilon$-N-dimethyllysine 및 3-methylhistidine의 방사능의 합계와 일치하였다. Acetyl 화의 경우 각 histone의 분획들을 trypsine과 Pronase로 가수분해하여 얻은 peptide와 amino 산들을 exclusion chromatography 및 ion exchange chromatography로 분리하였다. Acetyl 화를 행하였을 때는 arginine-rich 분획인 f2a1, f2a2 및 f3에만 incorporate 되었다. Histone의 각 분획중 f2a1이 다른 분획에 비하여 방사능이 가장 높았으며 f2a2, f3, f2b 및 f1의 순으로 방사능이 낮어진다. 각 분획의 방사능은 그의 전부가 $epsilon$-N-acetyllysine 및 ${alpha}$-N-acetyllysine이 갖인 방사능에 기인하였다. Lysine-rich histone 분획인 f1과 f2b에는 acetylation이 일어나지 않았으며 따라서 $epsilon$-N-acetyllysine 및 $alpha$-N-acetyllysine을 검출할 수 없었다.
In order to observe the properties of histones of Sarcoma 180 ascites tumor cells, the various histone fractions isolated from the tumor cells following the methylation and acetylation were studied. Histone fractions f1, f2a1, f2a2, f2b and f3 were prepared from isolated nuclei which had been incubated in the presence of L-methionine-methyl-$^{14}C$ and sodium acetate-1-$^{14}C$, respectively. For the methylation, the various histone fractions were hydrolyzed in acid and the hydrolysates were chromatographed on an amino acid analyzer. Histones were methylated by the transfer of methyl groups to the free $epsilon$-amino groups of lysine and histidine residues in the polypeptide chain, after the histone molecules had been synthesized. The specific activity of the histone fraction f2a1 was greater than those of other fractions and the specific activities diminished in the order of f2b, f2a2, f3 and f1 fractions. Histone fractions f1, f2a1, f2a2 and f2b were found to contain radioactive $epsilon$-N-methyllysine. $epsilon$-N-Dimethyllysine was the predominant form of the modified amino acid and its concentration exceeds that of the $epsilon$-N-monomethyllysine by a factor of 1.7. Histone fractions f2a2 and f2b were found to contain radioactive 3-methylhistidine. Virtually all of the radioactivity in these histone fractions are recoverable from the $epsilon$-N-monomethyllysine, $epsilon$-N-dimethyllysine and 3-methylhistidine. For the acetylation, each of the histone fractions was digested with trypsin and Pronase, and the resulting peptides and amino acids were separated by exclusion chromatography and ion exchange chromatography. Only the arginine-rich fractions f2a1, f2a2 and f3 were found to be appreciably labeled with acetate-$^{14}C$. Among the histone fractions, f2a1 fraction had a considerably higher specific activity than the other histone fractions and the specific activities diminished in the order of f2a2, f3, f2b and f1 fractions. All of their radioactivities could be recovered as two major radioactive peaks which were identified as $epsilon$-N-acetyllysine and $alpha$-N-acetyllysine. The comparatively lysine-rich histone fractions f1 and f2b were unlabeled and did contain $epsilon$-N-acetyllysine and $alpha$-N-acetyllysine.
