ABIOTIC PRODUCTION OF PRIMITIVE PROTEIN AND FORMED 



MICROPARTICLES* 



Sidney W. Fox and Shuhei Yuyama 

 Institute for Space Biosciences, The Florida State I'niversity, Tallahassee, Florida 



This presentation of results with a thermal model of origins will focus par- 

 ticularly on some of the properties of the microparticles which emerge there- 

 from. The more purely chemical aspects of the model have been treated else- 

 where.'"^ Although the significance of the particles found is much ditTerent 

 in this context than in others, salient features of the experimentally derived 

 scheme of origins will, however, again be reviewed here. 



One of the popular assumptions which had to be abandoned before the re- 

 search could proceed was the widely held belief that heating amino acids above 

 the boiling point of water will yield only dark, unworkable products. This 

 evaluation has been a common one in the experience of many organic and 

 biological chemists and has been documented many times.** If, however, one 

 follows the suggestions from analyses of evolution at the molecular leveF it 

 becomes possible simultaneously to condense thermally all of the amino acids 

 common to protein. The products contain each of these amino acids and 

 have many of the properties of protein. The necessary conditions are the use 

 of a sufficient proportion of aspartic acid or lysine and an initially dry state. 

 Heating can be at 170° for 3 hours. '^•' The product is a light amber in color 

 when sufficient aspartic acid is used, and, like protein, it may then be further 

 purified by dialysis and reprecipitation by salting out the polymer from aque- 

 ous solution. 



A second heresy concerns the belief that heat has generally been thought to 

 be a reliable agent for denaturation of protein. Not so generally known is the 

 fact that this process is "extraordinarily sensitive'"^ to the amount of water 

 present.^ Also, enzymes are more stable when dry}'* Accordingly, the pro- 

 duction of biologically significant polymers by heating amino acids is not 

 precluded. 



After extensive study of thermal copolymerization of simple combinations of 

 amino acids, initial evidence that these processes could be effected simultane- 

 ously was obtained by chromatography.'' End group assay'' '^ showed that 

 molecular weights were above that of insulin' (6000 for insulin, or approxi- 

 mately 3000 per end group). With lysine, thermal polymers of mean molecu- 

 lar weight over 300,000 have been demonstrated in the ultracentrifuge.^^ The 

 two criteria of qualitative composition and molecular weight are common to 

 the only two textbook definitions of protein that we have found." ■'- 



Of particular interest is the fact that polymerization is aided by phosphoric 

 acid,'5 7.i3 polyphosphoric acid, or ATP,!^!^ and especially, that the minimal 



*The work reported in this paper was supported in part by Grant no. C-3971(04) of the 

 National Institutes of Health, U.S. Puljlic Health Service, and Grant no. NsG- 173-62 of the 

 National Aeronautics and Space Administration. Presented in part at the Symposium on 

 Extraterrestrial Biochemistry and Biology, American Association for the Advancement of 

 Science meeting, December 27, 1961, Denver, Colorado. Contribution no. 5 of the Institute 

 for Space Biosciences. 



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