CM A I'. 32] THE OBIGIN OF l^lh'K 855 



The experiments on the mechanism of the electric discharge synthesis of 

 amino acids indicate that a special set of conditions or type of electric discharge 

 is not required to obtain amino acids. Any process or combination of processes 

 that yield both aldehydes and hydrogen cyanide would have contributed to the 

 amount of a-amino acids in the oceans of the primitive Earth. Therefore, it is 

 not fundamental whether the aldehydes and hydrogen cyanide came from 

 ultraviolet light or from electric discharges, since both processes would con- 

 tribute. It may have been that electric discharges were the principal source of 

 hydrogen cyanide and that ultraviolet light was the principal source of alde- 

 hyde, so that the two processes complemented each other. 



B. Ultraviolet Light 



It is clear from Table I that the greatest source of energy would be ultra- 

 violet light. The effective wavelengths would be CH4< 145o'A, H20< 1850 A, 

 NH3<2250A, CO < 1545 A, CO2<1690A, N2<1100A and H2 < 900 A. It is 

 more difficult to work with ultraviolet light than with electric discharges because 

 of the short wavelengths involved. 



The action of the 1849 A Hg line on a mixture of methane, ammonia, water 

 and hydrogen produced only a very small yield of amino acids (Miller, 1957a). 

 Only NH3 and H2O absorb at this wavelength, but apparently the radical 

 reactions formed active carbon intermediates. The limiting factor seemed to be 

 the synthesis of hydrogen cyanide. 



Groth (1957) and Groth and von Weyssenhoff (1957) found no amino acids 

 produced by the 1849 A line with a mixture of methane, ammonia and water, 

 but amines and amino acids were formed when the 1470 A and 1295 A lines of 

 argon were used. The 1849 A line produced amines and amino acids with a 

 mixture of ethane, ammonia and water. The mechanism of this synthesis was 

 not determined. Terenin (1957) has also obtained amino acids by the action of 

 the krjrpton lines on methane, ammonia and water. 



We can expect that a considerable amount of ultraviolet light of wavelengths 

 greater than 2000 A would be absorbed in the oceans, even though there would 

 be considerable absorption of this radiation by the small quantities of organic 

 compounds in the atmosphere. Few experiments have been performed which 

 simulate these conditions. 



Ellenbogen (1958) has worked with a suspension of ferrous sulfide in aqueous 

 ammonium chloride through which methane was bubbled. The action of ultra- 

 violet light from a high-pressure mercury lamp gave small quantities of a sub- 

 stance with peptide frequencies in the infrared. Paper chromatography of a 

 hydrolysate of this substance gave a number of spots with ninhydrin, of which 

 phenylalanine, methionine and valine were tentatively identified. Unfor- 

 tunately, this experiment is difficult to reproduce. 



Bahadur (1954) has reported the synthesis of amino acids by the action of 

 sunlight on concentrated formaldehyde solutions containing ferric chloride and 

 nitrate or ammonia. Pavlovskaya and Passynskii (1958) have found a number 



