Primitive and Present-day Photobiological Processes 



195 



Table 3 



Effect of catalysts 



* Note: + denotes quantity at least doubled j — denotes quantity at least halved; 

 O denotes no effect. 



In our attempts to find a system in which the amino acid yield was higher we tried 

 7 catalytic systems, 2 heterogeneous and 5 homogeneous. Their effects are Usted in Table 3. 

 A positive effect is recorded where the glycine spot is a factor of 2 more intense than the 

 standard. 



In the second kind of experiment we started out with amino acids, and attempted to 

 elucidate the effect of further irradiation on them. To a considerable extent the simple 

 amino acids break down to smaller molecules, glycine and alanine both giving easily 

 detectable amounts of ammonia and CO2. 



However, glycine also gives one product in fairly large yield, moving with an i?F of 

 about 037 in butanol-acetic acid which we first confused with alanine, but later showed 

 by co-chromatography to be sUghtly slower. This substance stiU awaits final identification, 

 but we suggest tentatively that it is glycylglycine. Its formation is increased in the presence 

 of small amounts of riboflavin, but inhibited in the presence of cysteine. 



The irradiation of cystine leads first to the formation of cysteine, and then to the 

 formation of a great array of products. Among these some of the amino acids have been 

 tentatively identified, but there are a great number of other types of chemical substance 

 also present. 



This result is interesting in view of the result reported by Fox recently of the thermal 

 formation of a similar array of compounds from cystine. 



This last result means that if there have been at any time conditions on the Earth imder 

 which comparatively large quantities of cysteine or cystine were formed, subsequent 

 radiative or thermal transformations may have led to the production of a great array of 

 small organic amino acids and other functional molecules close to each other. This is 

 presumably the requirement if the very improbable association of a particular set of such 

 molecules is to become significantly more probable. 



REFERENCES 



1. S. L. Miller, J. Amer. chem. Soc, 77, 2351, 1955. 



2. A. I. Oparin. The Origin of Life, 2nd ed. Dover PubUcations, New York, 1953. 



3. J. A. Barltrop, p. M. Mayes & M. Calvin, J. Amer. chem. Soc, 76, 4348, 1954. 



4. H. Theorell, Currents in Biochemical Research (Ed. D. E. Green). Interscience, 



New York, 1956, p. 275. 



5. G. Wald & P. K. Brown, J. gen. Physiol., 35, 797, 195 1. 



6. E. Marre, R.C. Accad. Lincei, 18, 88, 1955. 



7. B. L. Strehler, The Luminescence of Biological Systems. American Assoc, for the 



Advancement of Science, Washington, 1955, p. 199. 



8. W. M. Dale, Discuss. Faraday Soc, 'Radiation Chemistry', 1952, p. 293. 



9. E. S. G. Barron, Symposium on Radiobiology. John Wiley, New York, 1952, p. 216. 

 10. W. GORDY, W. B. Ard & M. Shields, Proc nat. Acad. Sci., Wash., 41, 983, 1955. 



