SESSION III. DISCUSSION 293 



A. M. GoLDOVSKiï (U.S.S.R.) : 



The Significance of the Multivariance of Chemical Reactions in the Processes 

 of Emergence and Development of Life on the Earth 



We wish to draw attention to one of the properties of chemical reactions which un- 

 doubtedly had a decisive importance in the emergence and development of life. We 

 have used the term 'multivariance' for this property [i]; it refers to the fact that, in each 

 chemical reaction in which organic substances are involved, the meeting and interaction 

 of the reacting molecules always leads to the reaction developing in a multiplicity of 

 directions with the formation of numerous products. Any reaction of organic substances 

 under the ordinary conditions of artificial organic synthesis will serve as an example [2]. 

 However, even when reactions occur under gentler conditions, approaching those of 

 synthesis within the organism, we m^eet with the same multivariance of chemical reactions 

 and the formation of mixtures of products [2]. 



The multivariance of reactions must, of course, inevitably occur even when the reac- 

 tions take place within an organism. This property of reactions is to be found, not only in 

 non-enzymic reactions, but also in the fundamental enzymic reactions occurring within 

 the organism, for it is entailed by the actual mechanism of the reaction. Every enzyme or 

 collection of enzymes, like any other catalyst, determines the general direction, the general 

 character of a particular biochemical process, but does not prevent the occurrence, within 

 limits, of a multiplicity of different variants, which are inevitably entailed by the actual 

 course of the chemical reactions and lead to the formation of mixtures of substances [3]. 

 For example, in experiments on the enzymic synthesis of polysaccharides in vitro by the 

 action of potato Phosphorylase on glucose i -phosphate, there are formed mixtures of 

 polysaccharides with different molecular weights [4, 5, 6], which are entailed by the actual 

 mechanism of the reaction of polymerization or polycondensation. 



Returning to in vivo synthesis within organisms, we find here unmistakable signs of the 

 multivariance of biochemical reactions. This is seen in the fact that, in every organism, 

 each narrow group of substances consists of a whole series (mixture) of very similar sub- 

 stances, with a common structural plan characteristic of the particular narrow group of 

 substances, but with differences in their structural details (in high polymers there are 

 differences in molecular weight and in degree of polymerization)*. This multiplicity 

 of substances is, as our work has shown [7], a completely regular occurrence and applies 

 to all groups of substances in the organism (the law of multiplicity of the representatives 

 of every group of substances in the organism). For example, many proteins, especially 

 protein enzymes, which are considered to be individual substances, may be separated into 

 fractions having very similar properties j the glyceride components of fats are, in every 

 organism, composed of mixtures of many triglycerides; multiplicity is characteristic of 

 phosphatides, carotenoids, tocopherols, sterols, antibiotics, etc. [7]. 



The quantitative relationship between similar substances within a narrow group in 

 any particular organism is usually such that one substance predominates while others are 

 present in lesser amounts, so that one may make a provisional quantitative distinction 

 between the main and the subsidiary substances. 



Similarly, within the limits of each complicated biochemical reaction, one may make a 

 provisional quantitative distinction between the main and subsidiary (side) reactions on 

 the basis of their intensity. Every biochemical process is made up of a 'bundle' of bio- 

 chemical reactions which must lead to the production of a multiplicity of similar com- 

 pounds. The more the course of the side reactions deviates from that of the main reaction, 

 the greater will be the differences, in quantity and structure, between the by-products 

 and the main product. 



As we shall see, multivariance occurs in chemical reactions no matter under what 

 conditions they take place, whether they be the severe conditions of organic chemical 

 synthesis or the gentler conditions of biosynthesis. Thus multivariance must have occurred 

 during the emergence of Ufe as well as during all the later stages of its development. 



The multivariance of chemical reactions may have been of great significance even during 

 the primary formation of organic compounds and their further transformation. It appears. 



* The multiplicity of substances in an organism depends on a number of factors but, 

 obviously, the most important cause is, in fact, the multivariance of chemical reactions 

 in the organism. 



