THK PHOTE1XS AND THEIR METABOLISM 



95 



Number of amino acids 



10 

 11 

 12 

 13 

 14 

 15 

 10 

 17 

 18 

 11) 

 20 



Number of possible compounds 



3,628,800 



39,016,800 



479,001,600 



0,227,020.800 



87,178,21*1,200 



20 ? 922,7S9,8S8,000 



355,687,428,096,000 



6,402,373,705,72^,000 



121,645,100,408,832,000 



2,432,902,008,176,040,000 



If it were possible to arrange twenty amino acids in one straight line 

 forming a protein molecule, 2,432,902,008,176,640,000 different kinds 

 of protein molecules could be formed. This figure, however, does not 

 vet by any means complete the list. While most of the amino acids are 

 alle to form unions with other amino acids in a straight line, the dibasic 

 mono-ainino acids and the diarnino acids are able to form branched chain 

 compounds. 



COOH 



nr, 



CHN 



\H 



Aspartic 

 acid 



H\ 



N CII 



COOH 



cir. 



CIIXH 



( T)OH 



I 

 C1I 2 



H\| 



NCII 

 H/l 



COOH 



Glyoocoll 



Alanin 



Aspartic acid 



HN CH, COOH 



HKCH 



COOH 



