SYXriIl.SIS OF ()R(,A\I(: COMl'orXDS \\\ I()\I/I\(; RADIATION 

 SYNTHESIS OF BIOLOGICAL INTEREST 



We are conccnud lure not so imu h with racliaticjn-induccd modification of 

 hiolos^ically active compounds as with the production of simple compounds, 

 which could conceivably react together to form a nuclcoprotein. For many 

 \ears, scientists have been aware of the significance which attaches to the 

 pioduction of protein precursors in ionizing radiatif)n fields. Perhaps the 

 earliest discoxery was Loeb's production in 1913 of glycine in a silent 

 discharge reaction in a mixture of carbon monoxide, ammonia and water 

 vapour--. 



A brief simimary of gas-phase reactions of carbon compounds, which 

 occur in electric discharges is as follows: 



CO + NH.J + H2O > Glycine 



> HCN 



CH4 + NH3 



CH4 + N., 



CO -F N, + H., 



C.,U, + N, \ _ 



C2H4 + HCN J 



Nitriles, isonitriles 



C2H4 + NH3 ^ Amines 



CO + H., > HCHO 



CH4 + COo > HCHO + CH.CHO 



CH4 + CO > CH3CHO 



C2H2 + CO > Acrolein 



CO + H.,0 \ 



CH4 + H2O J 



-^- 



Acids 



It is to be noted that unidentified 'polymers' have been found in each 

 case and, furthermore, that it is doubtful that a complete analysis has been 

 carried out in any case for the simpler products. Another important feature 

 is that it is seldom clear whether the reported synthesis occurred as a primary 

 reaction in the gas phase or as a secondary process in a condensed phase. 



Such experiments would have had greater biological significance if they 

 had been conducted always in a reducing atmosphere. The conclusions 

 reached by Urey* in his extension of Oparin's^ theory are that the planets 

 were formed at low temperatures ( < 300°C) and that the early forms of life 

 were developed in a reducing atmosphere of hydrogen. Primary radiation 

 chemical reactions to produce precursors of living material should therefore, 

 presumably, always involve the participation of gaseous molecular or atomic 

 liydrogen. It is a matter beyond the scope of this paper to discuss the next 

 two stages in detail — the aggregation of the precursors into living matter and 

 the maintenance of life in a highly reducing atmosphere. A matter requiring 

 further argument is the formation of such precursors from oxygen-containing 

 gases, which imjjlics the existence of circumstances wliich could not be 

 regarded as invariably reducing. 



In a recent series of papers'-^, Miller has investigated the formation of a 

 series of amino and hydroxy acids and miscellaneous compounds in a system 



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