On the Origin of the Fore-protein 



193 



on Dowex 50 x 8 with citrate buffer (pH 3-42) as elution agent (Fig. 4). The 

 presence of aspartic acid, glycine and alanine was very clearly demonstrated. 

 These amino acids were further identified by two-dimensional chromatography 

 after they were converted to dinitrophenylamino acids (Fig. 5). 



200 



pH 3-42 citrate buffer, ml 

 Column : Dowex 50 X 8 100x0-9cm 37-5 °C 



Fig. 4. Hydrolysate of reaction product of HCN with poly-dehydroalanine. 



1-5M phosphate buffer ■ — 



Fig. 5. Hydrolysate of reaction product of HCN with poly-dehydroalanine. Paper 

 chromatogram of DNP-derivatives. 



The formation of aromatic and heterocyclic amino acids in the fore-protein 

 could have occurred by the condensation of methylene group of glycyl residue 

 followed by hydrogénation (Fig. 6). The chemical structure of phenylalanine, 

 tyrosine, tryptophan and histidine, in which one methylene group is situated 

 between an aromatic or heterocycHc nucleus and a glycine group might support 

 the above-mentioned mechanism of their formation in the fore-protein. 



The formation of valine, leucine and isoleucine might have resulted from the 

 direct addition of propylene, fjobutene and but-2-ene respectively as shown in 

 Fig. 6. Experimental evidence for such a mechanism is not yet sufficient. Every 

 attempt to introduce a sec.-hutyl group to polyglycine chain with basic catalysts 

 has failed. When, however, polyglycine dispersed on Japanese acid clay was 



13 



