470 Annals New York Academy of Sciences 



obtained glycine, aspartic acid and possibly diaminosuccinic by irradiating 

 with j8-rays an aqueous solution of ammonium acetate. Paschke et al.,^^ 

 irradiated solid ammonium carbonate with the 7-rays from a cobalt-60 source 

 and obtained glycine, 2 other ninhydrin-positive compounds, 1 of which was 

 tentatively identified as alanine, and ammonium formate. 



It is known that formic acid and simple aldehydes are formed by the action 

 of ionizing radiation over aqueous solutions of carbonic acid.-^-^^ It is also 

 known the glycolic acid is produced by the irradiation of formic acid.''^ There- 

 fore, it is conceivable that glycine and other amino acids could also be obtained 

 by the irradiation of aqueous solutions of ammonium carbonate. 



Although from the above experiments it is evident that amino acids can be 

 synthesized from partially oxidized compounds such as ammonium carbonate, 

 it would seem more logical, on the basis of theoretical considerations,^^ to study 

 the irradiation of aqueous mixtures of reduced carbon and nitrogen compounds, 

 such as methane and ammonia. This has been done by Dose et o/.,^'*'^^ and a 

 larger number of amino acids and bases have thus been obtained. More 

 recently, Calvin^® and Palm and Calvin^'' have irradiated mixtures containing 

 C^*-methane, ammonia and water, among other compounds, with 5 MeV elec- 

 trons and have obtained a number of amino acids including glycine, alanine, 

 and aspartic acid. Radiochemical and nonradiochemical mechanisms of syn- 

 thesis may be involved in this case because hydrogen cyanide, which is known 

 to condense into products which yield amino acids, was also formed in sub- 

 stantial amounts in these experiments. 



Apart from these amino acid syntheses, it may be added that the 7-irradia- 

 tion of mixtures of carbon dioxide and ethylene at room temperature yields 

 significant amounts of long chain carboxylic acids containing as many as 40 

 carbon atoms. ^^ Also, high energy proton or electron irradiation of methane, 

 ammonia, and water at 77° K., in a simulated cometary model, yields a number 

 of organic compounds. ^^ 



(4) From reactive precursors. As pointed out earlier it is known from astro- 

 nomical observations that in the atmospheres of carbon stars, very reactive 

 diatomic combinations of carbon, nitrogen, oxygen and hydrogen are formed. 

 These combinations are presumed to diffuse out and eventually become part of 

 interstellar matter, cosmic bodies and protoplanets, being converted in the 

 process into simple but reactive compounds. These may include hydrogen 

 cyanide, acetylene, carbon monoxide, formaldehyde, acetaldehyde, ammonia, 

 hydrazine, and hydroxylamine among others. Some of these compounds have 

 also been produced in the laboratory from aqueous ammonia-methane mixtures. 



Thus, it was considered of interest to discover whether some of these com- 

 pounds are sufficiently reactive to yield amino acids, and other biochemical 

 compounds in the absence of electrical discharges, ultraviolet light, or ionizing 

 radiation. 



It was first shown in our laboratory^® that aqueous mixtures of formaldehyde 

 and hydroxylamine hydrochloride at moderate temperatures and under slightly 

 acidic conditions yield large amounts of glycine and smaller amounts of alanine, 

 (3-alanine, serine, threonine, and aspartic acid, the last 3 having been only 

 identified by paper chromatography. Amino acid amides, glycinamide in 



