~1 



1 



From Schmidt's Chemistry of the Amino Acids and Proteins. 

 Courtesy of Charles C. Thomas, publisher, Springfield, Illinois. 



Fig. 5-8. Cystine. 



From lluwk and I'.crgeim, Practical I'hysioloyical Chemistry. 

 Courtesy of P. Blakiston's Son & Co.. Inc. 



Fig. 5-9. Histidine. 



115 



