452 



a. g. pasynskiï 

 Table i 



From Table i it may be seen that the system which we studied could stabilize 

 itself by altering the stationary state when the kinetic parameter A was changed 

 by 7-12% and correspondingly when the stationary state is changed by 2-7%. 

 If the kinetic parameter A is altered by 16-26% the change in the stationary 

 state no longer follows a curve of the same type as curve I in Fig 6 but follows 

 one like curve II in Fig. 6, with a loss of ability of the system to compensate 

 by a change in the stationary state. It must be noted that the limiting values of 

 these changes are not the same in the various cyUnders and under all experi- 

 mental conditions. Thus, if the diameter of the membrane was 37 cm and 

 5 = 0-142 the change over to a curve like curve II in Fig. 6 occurred at values 

 of A between i-i2 and 1-22, while, when the diameter of the membrane was 

 2*4 cm and 5" = 0-0852 it occurred at values of A between 1-075 and i-io. 

 Similarly, in regard to the size of changes in the stationary level, the limiting 

 figure Ues at 0-925 in cylinder III, at 0-970 in cylinder II, and apparently at 

 about 0-978 in cylinder I (and A = 1-04). Thus, the 'threshold of endurance' of 

 an open enzymic system depends on the intensity of the processes of diffusion 

 and chemical transformation in the system. 



Thus, even in the simplest enzymic reactions in open systems which have 

 been studied, there appear a number of properties which are different from 

 those of the same reaction when it occurs in enclosed systems. Among these 

 properties are: (i) The possibihty of maintaining, in the system, concentrations 

 of the reacting substances which do not vary with time (stationary), while, in an 

 enclosed system, these concentrations are bound to fall; (2) the possibility of 

 the catalysts (enzymes) affecting, not only the rate of the reaction, but also the 

 apparent equilibrium of the system, i.e. the stationary concentrations of the 

 reacting substances; (3) the ability of the system to undergo reparative processes 

 (homoeostasis) when the external conditions change (Figs. 3-7); (4) the power 

 of dynamic stabilization of the stationary state, which is, in essence, an extension 



