364 



ERWIN CHARGAFF 



lOOr 



60 



■ adenine + thymine 

 E3 guanine + cytosine 



T 12 1234 23 23 455 2345 234567 1234 



20 



I II III IV V VI \1I 



Fig. 4. Composition of sodium deoxyribonucleate fractions (in moles per 100 g.- 

 atoms of phosphorus) prepared by the fractional dissociation of calf thymus nucleo- 

 histone with salt solutions of increasing strength. Each block (I-VII) represents 

 a separate fractionation run; the consecutively numbered bars within each block 

 represent individual fractions, with the NaCl concentration rising from left to right. 

 The first column (T) indicates the average composition of the total deoxyribonucleic 

 acid. (Taken from Chargaff et al}^^) 



J^ adenine -f- thymine 

 guanine -f- cylosine 



Wi guanine ■>■ hydroxy met hy Icy losme 

 lOOrS ,l„„,? 3 4 T ,,l,^.,2,.,,,3„^'^,^ 



50 I GO 



CALF THYMUS 



50 100 



PIG LIVER 



50 100 



HUMAN SPLEEN 



50 100 



C0LIPHA6E T6 



Fig. 5. Composition of fractions (in moles per 100 g. -atoms of phosphorus) pre- 

 pared by the fractional dissociation of artificial histone complexes with the indicated 

 sodium deoxypentose nucleate preparations. The abscissa indicates the proportion of 

 original nucleic acid P recovered in each fraction. Compare Fig. 4 for other explana- 

 tions. (Based on the results of Crampton el alP-^^) 



