Differential scanning calorimetric study of antibiotic distamycin A binding with chromatin within isolated rat liver nuclei

Figures & data

Figure 1. DSC profiles of rat liver nuclei in buffer A: 1 – control; 2 – with Dst (molar ratio Dst/DNA =0.1). I, II, III – designations of thermal transitions.

Figure 2. DSC profiles of rat liver nuclei in buffer B: 1 – control; 2 – with Dst (molar ratio Dst/DNA =0.1). I, II, III – designations of thermal transitions.

Table 1. Enthalpies of thermal transitions for rat liver nuclei^a.

	ΔHexc
Treatment	Total	I	Additional	II	III
Buffer A (polyamines)
Control	24.7	4.1 (17%)	1.0 (4%)	11.7 (47%)	7.6 (31%)
+Dst	34.5	2.6 (7.5%)	2.8 (8%)	10.4 (30%)	17.6 (51%)
Buffer B (Mg^2+)
Control	35.8			31.5 (88%)	3.9 (11%)
+Dst	33.7	2.7 (8%)		24.5 (73%)	6.0 (18%)

^a ΔH_exc are expressed in kJ/mol nucleotides of DNA and in the percentage of total ΔH_exc. The results represent the mean of at least three experiments with standard deviation from mean not exceeded 5%.