52 A. G. PASSYNSKY 



polymers, e.g. polyethylene, irradiated with a beam of fast electrons 

 (Karpov and Zverev, 1955) was carried out. The formation of but one 

 chemical bond or "cross-link" between molecular chains as a result of 

 contraction of the distance between them from 4-5 A to 1-54 A was 

 shown to bring about a disturbance of the regularity of structure at 

 a distance of scores of atomic groupings as a result of the transmission 

 of tensions arising along molecular chains. Formation of double-bonds 

 in an iiTadiated polymer acts in the same fashion. It was pointed out 

 by these authors that a relatively small number of strong distortions 

 of the lattice in polyethylene crystals as a result of radiochemical 

 reactions in some 1 per cent of polymer links results in a conversion of 

 the bulk of the substance from the crystalline to the amorphous state. 



In our work with Tongur (196U) the action of transverse "cross-links" 

 in a monomolecular layer of DNP (deoxyribonucleoprotein) on the 

 structure of the monolayer was studied. The DNP monolayer was 

 obtained on a Langmuir balance by applying microdrops of an 0-04 per 

 cent DNP solution (mol. weight 4-5x106 and 8 x 10^; N/P-3-8) in 

 1 M NaCl to a 38 per cent aqueous solution of (NH4)2S04. This lower 

 phase was chosen in order to decrease the solubility of the nucleoprotein 

 api^lied to facilitate the conditions of its spreading. The thickness of 

 the DNP monolayer was about 23 A. Formation of transverse "cross- 

 links" was achieved by the addition of 2 per cent formaldehyde to the 

 lower phase. It was shown that without formaldehyde in the lower phase 

 pressure-area curves which characterize the mechanical properties of 

 the monolayer were rather constant for native and degraded (down to 

 M = 20,000) DNP preparations, while the value of the monolayer area 

 was, respectively, 0-36 and 0-30 m^/mg (some decrease of the area is 

 due to the dissolution of a portion of the most altered molecules in the 

 lower phase). On the contrary, in the jjresence of "cross-links", i.e. in 

 the lower phase with formaldehyde, stable distortions of the monolayer 

 structure arise, accompanied by an appreciable increase in the area/mg. 

 For example, for native DNP the area of the monolayer increases from 

 0-34 to 0-43 m2/mg, for the treated DNP from 0-26 to 0-36 m2/mg; the 

 monolayer being compressed, it remains in a somewhat expanded state. 

 This result, which is very similar to the data already mentioned for thin 

 films of polymers, shows that radiation-induced formation of "cross- 

 links" between polynucleotide chains in DNA and DNP monolayers 

 leads to stable distortions of monolayer structure which, by their very 

 nature, must result in a change in the permeal)ility of these thin layers. 



The influence of this factor on the course of enzymic reactions was 

 studied by Passynsky and Volkova in the following model system, A 

 preparation of crystalline peroxidase, in the form of a fine dry powder, 



