[Nucleoprotein melting. II. Melting of irreversible DNA-protein complexes].

Three with different complexity models: single-stranded, periodic theeropolymer, two-stranded periodic heteropolymer and complex of DNA with irreversible bound proteins have been considered. It is shown that the individual bands on the differential melting curve appear if the length of protein bound regions exceed 25 base pairs. In this case the melting temperature of free and protein bound regions depends on their reciprocal length in almost linear manner. Moreover, the temperature of the peak corresponding to the protein bound regions is independent on the length of the adjacent free DNA regions if their length exceeds 15 base pairs. If the length of free and protein bound regions exceed 300 base pairs, their melting temperatures becomes almost equal to that of infinitely long polymer with the analogous structure. A simple method for determination of length of the free and the protein bound regions length has been proposed.