484 



Annals New York Academy of Sciences 



to be reckoned with. In such zones further chemical reactions are entirely 

 possible to yield more compUcated systems. 



The effects of ultraviolet light on a mixture of methane, water, and ammonia 

 have been studied also by Miller. ^° Only a very small yield of amino acids 

 could be obtained. Groth, and separately, Terenin, examined similar reac- 

 tions.'^ Ellenbogen irradiated a reaction mixture containing FeS, NH4CI, 

 H2O, and CH4 with ultraviolet light and observed the formation of a substance 

 the infrared absorption spectrum of which indicated peptide bonds. ''^ Ap- 

 parently other similar experiments to synthesize amino acid sequences held 

 together by peptide bonds have not yet been successful. 



The effects of visible light on the formation of many different organic com- 

 pounds have been examined extensively in the literature on photochemistry 

 and need not be discussed in this paper. 



AMINOACID AND PROTEIN STRUCTURE 



R R R 



— NH — CH— CO— NH — CH — CO— NH — CH- 



CO — 



V. 



H 

 I 



/ 



Y 



H 



I 

 ^N — 



-C C- 



II 

 



H 



II 



H 



/ 



c4_ 



-N- 



C 



II 

 



Figure 2. 



In a number of experiments high energy particle radiation as well as x- and 

 7-rays were utilized. Dose and Rajewsky obtained amino acids and amines 

 from gaseous mixtures of NH3 , N2 , H2O, CH4 , and CO2 with X-rays.'^ The 

 action of 2 Mev electrons on CH4 , H2O, and NH3 yielded also amino acids.''* 

 Calvin irradiated CH4 , NH3 , H2O, and PH3 in the gas phase with electrons.'^ 

 Radiochemical analysis showed the presence of small quantities of nucleic acid 

 bases, substances which are of vast importance in genetic material (figure 3). 



Garrison et al.,^^ used 40 Mev helium ions to obtain formic acid and formal- 

 dehyde from carbon dioxide. Aqueous formic acid yielded formaldehyde and 

 oxalic acid.""' Hasselstrom and Henry also obtained oxalic acid from Ca- 

 (HC03)2 and NH4HCO3.'' Succinic, tricarbolic, malic, citric, and malonic 

 acid were isolated from the reaction of aqueous acetic acid with helium ions.'* 

 Also, glycine and aspartic acid were the products in the 2 Mev electron bom- 

 bardment of acjueous ammonium acetate.'^ 



All of the previously mentioned radiation reactions occur in gaseous or liquid 

 systems, but even reactions in the solid state may be carried out. For example, 

 high doses of 7-rays on solid (NH4)2C03 yielded formic acid and glycine.^^ 



