INTRODUCTION 



4. Leucine, C 6 H 13 NO 2 , or o-aminoisocaproic acid. 



CH 3 v 



\CH . CH 2 . CH(NH 2 ) . COOH 



5. Isoleucine, C 6 H 13 NO 2 , or o-amino-/3-methyl-)8-ethyl-propionic acid. 



CH,\ 



\CH . CH(NH 2 ) . COOH 



6. Phenylalanine, C 9 H U NO 2 , or 0-phenyl-a-aminopropionic acid. 



C 6 H 5 .CH 2 .CH(NH,).COOH 



7. Tyrosine, C 9 H n NO 3 , or /3-parahydroxyphenyl-o-aminopropionic acid. 



HO . C 6 H 4 . CH 2 . CH(NH 2 ) . COOH 



8. Serine, C 3 H 7 NO 3 , or )3-hydroxy-o-aminopropionic acid. 



CH 2 (OH) . CH(NH 2 ) . COOH 



g. Cystine, C 6 H 12 N 2 O 4 S 2 , or dicysteine, or di-(-thio-a-aminopropionic acid). 

 HOOC . CH(NH 2 ) . CH 2 . S S . CH 2 . CH(NH 2 ) . COOH 



B. Monoaminodicarboxylic acids. 



10. Aspartic acid, C 4 H 7 NO 4 , or aminosuccinic acid. 



HOOC . CH 2 . CH(NH 9 ) . COOH 



11. Glutamic acid, C 5 H 9 NO 4 , or o-aminoglutaric acid. 



HOOC . CH 2 . CH 2 . CH(NH 2 ) . COOH 



C. Diaminomonocarboxylic acids. 



12. Arginine, C 6 H 14 N 4 O 2 , or a-amino-S-guanidinevalerianic acid. 



\NH . CH 2 . CH 2 . CH 2 . CH(NH 2 ) COOH 



13. Lysine, C 6 H 14 N 2 O 2 , or a, e-diaminocaproic acid. 



H 2 N . CH 2 . CH 2 . CH 2 . CH 2 . CH(NH 2 ) . COOH 



D. Heterocyclic compounds. 



14. Histidine, C 6 H 9 N 3 O 2 , or j8-imidazole-a-aminopropionic acid. 



CH 



</ \ 



N NH 



CH = C CH 2 .CH(NH 2 ).COOH 



15. Proline, C 5 H 9 NO 2 , or o-pyrrolidine carboxylic acid. 



CHo CH, 



CH 2 CH. 



COOH 



16. Oxyproline, C 5 H 9 NO 3 , or 7-hydroxy-o-pyrrolidine carboxylic acid. 

 HO.CH CH 2 



CH., CH.COOH 



